Let’s start with defining what I mean by a ‘Rogue’ class. Rogues are character classes that rely on speed and special items or moves that hit for large effect in debuffs/status effects or large damage on weaknesses.
Typical/classic examples are the Thief (stealing and daggers), Ranger (ranged weapons and traps), Ninja (thrown weapons and concealment) and varieties of swordsman or skilled fighter classes. Examples from other media would include Legolas (Lord of the Rings series), Black Widow and Deadpool (Marvel comics and films), Batman (DC comics and films) and Judeau (Berserk manga and anime), among many others.
Classic RPG classes like Monks (bare hands and chi-powered attacks and support), Spell Fencers (rapiers and using magic to increase the power of attacks) or Red Mages (low level spells of all types and quick casting) should not be considered rogues due to their reliance on Magic/Mana and propensity for high DPS or advanced support roles.
Speed Mechanics -
In ATB (Active Time Battle like most Final Fantasy games) rpgs, you can make their time bar fill faster, allowing them to perform more moves overall or faster.In turn based systems a character can deal damage a certain number of times during an attack.Higher dodge rates can also make them feel faster this still relies on (adjusted) RNG and often feels unsatisfying or OP, depending on how often the dodges actually proc.
In more action oriented games you can increase their attack rate at the risk of making them have a much higher DPS than other attack oriented classes. You can also just literally make the character move faster when the player is controlling their movements. This has to be adjusted carefully, however, because players will almost always prefer characters that can move faster than others. If you have one class that feels significantly faster than another class, players will feel drawn to that class despite the virtues of other classes.
Mechanics to do with a character's speed impact the gamefeel much more than how it affects the other mechanics in the game. As such, it is important to sort out how speed will factor into gameplay early on in development.
Unfortunately few action RPG games feature a system where how heavy your armour is affects your movement speed. This plays into rogue type characters because in order to have faster movement, one must wear lighter armour or clothes. This means that there's a greater need to dodge attacks and ensure that the enemy cannot easily make moves or attack you. If one used heavier weapons but still in lighter armour, they would tend to get hit much more due to the slower moveset of the weapon limiting one's ability to dodge and therefore be a bad combination. This is a good system to encourage people to give more thought to their character’s loadout and playstyle without forcing a static class system onto them.
Weakness Attacking Mechanics -
Low per attack damage usually results in not being good against higher defence enemies, making it important to add a mechanic to hit the weak points of the enemy to deal proper damage. This is traditionally represented through having a higher critical hit rate than other classes but has the same RNG problem as with dodging, explained above. Having critical hits/damage tied to percentages and calculations has almost no skill associated with actually scoring the higher damages, outside of min/maxing equipment and skills which doesn't change how the game plays during fights.
The other option is to have support moves that cause status effects or debuffs to the enemy, making them easier to fight against or weaker to individual attacks. Things like stuns, slows, confusion and most prominently poison (or other DOT (Damage Over Time) statuses).Status effects themselves are a whole other kettle of fish to balance, and can make supposedly difficult enemies far too easyA common issue is to make bosses and other very tough foes immune to basically all status effects, making rogues useless in long and tough fights when it's not worth using status effects against easy enemies (why stun an enemy if they’d die faster with no consequences if you just did damage?)
A specific example of balancing status effects in Final Fantasy 9 is that the black mage (Vivi) and white mages (Garnet/Dagger and Eiko) between them have many status inflicting moves (stop, slow, sleep, silence etc), making them useful for fighting tougher regular enemies, e.g. inflicting silence on foes that make heavy use of magic attacks. In boss fights, however, most bosses are immune to a large number of status effects and make it feel pointless searching for those weaknesses they do have when you could instead be using the turns to inflict damage. The blue mage (Quina) can learn a spell that causes many status effects at once (Bad Breath), meaning that the boss will often get caught with 3-5 status effects. The MP cost of Bad Breath however limits how much the player will want to use it against regular enemies. This system strikes a clean balance forcing the player choose who to have in their party, the characters that are versatile in how they efficiently cause single statuses (or other damages) or the character that has a great variety within single costly moves that are better for larger, specific fights.
Dark Souls has a healthy approach to status effects. When you are ‘hit’ with an attack that has a status associated with it, you have a bar that gradually fills as you get hit more with that status. The more resistance to that status you have, the harder it will be for that bar to get filled. Once full, the status is applied.
What this does is make the skill of dodging attacks more important in the combat, as its not a die roll every time you get hit whether you’ll get the status (as per traditional implementations of status effects). You can see that the foe has a status effect in its arsenal and can plan appropriately, as opposed to being suddenly disadvantaged in the fight without being able to work around it. For a game like Dark Souls which has to be balanced for both PvE and PvP at the same time, this is an elegant solution, making different weapons better at giving status effects more easily balanced around that.
It also means that players have to work hard to give that status to an enemy, needing to fill their bar the same as theirs gets filled. This allows the status effects to be very powerful without upsetting the balance between players (provided the other players style is accounted for in balances) This requires the player to play in a different way to straight strength DPS, in that their focus os now on dealing many attacks swiftly in order to fill the opponents status bar as soon as possible. This need filters down to other decisions the player has to make, like weapons, equipment and carry load in order to make their actual movements match their attack style.
The fast melee attacking Dual Blades weapon type in the Monster Hunter series make for a clean and fun way to increase DPS through skill for people wanting to play like a rogue. With the Dual Blades you can attack very quickly, meaning that you can have time for dodging attacks and picking attack windows easier.
This is balanced with a lower damage per attack than other weapons and the weapon loses its edge (meaning less damage) very quickly. Amongst the many themes of Monster Hunter is that each of the weapon types have alternate uses or moves to complement the type of character class they create. As such, the Dual Blades have a system whereby you can enter Demon Mode. Activating Demon Mode increases the damage dealt by attacks and increases attack speed while sacrificing stamina. When your stamina runs out, you are kicked out of demon mode and must wait for your stamina to refill.
You also fill the Demon Gauge by attacking while in Demon mode, when that is full it further increases your attack speed and damage and also extends the time you can stay in this more powerful mode. This gives the player lots of choices to think about in when to activate the higher damage modes and also gives the player another mechanic to focus on during fights other than simply attacking. Low per attack damage is often balanced with unorthodox attacking moves, often dealing substantially more damage at some cost. The ability to Throw items or weapons is common for ninja classes in JRPGs, enabling them to deal large damage to a target at the cost of losing an item or more often an unused weapon in the party inventory. This is a pretty good DPS balance but can make the character too dependant on items, making them significantly less useful when the player has few funds or is far from a shop to replenish supplies. You may want the player to have to account for dwindling supplies vs winning fights quickly, however, and that can make for some desperate emergent moments.
Making a player dependant on items can often be a mistake because the player will want to conserve or hoard useful items and therefore not get a good grasp of what that character’s class is supposed to feel like. Even when they have many of a certain item, the player will often be wary of using them in case of a wasted opportunity. Alternate ways of replenishing items, such as looting or crafting should be considered if there is a desire to have the player spend long periods of play away from traditional ways of resupply.
Another thing is that if you have it balanced so that the player basically never runs out of an item or items, why make them items to collect and use at all? The Legend of Zelda: A Link Between Worlds has a system whereby all equipment uses the same meter; arrows, bombs, magic spells alike. This streamlines replenishing item use and means that the player rarely has to worry about being able to use items. Having said that, it is important to remember that the Zelda series has use of items to solve puzzles to progress, and almost never has a point at which a player cannot progress at all due to lack of supplies. Item Scarcity is another thing to consider when balancing rogue classes.
In summary; rogues in RPGs should be careful about balancing the RNG of moves and in how their speed manifests in gameplay. Rogues in action games need to stay far away from RNG and be heavily reliant on player skill and mechanics knowledge. Designers should think about where and how they want rogues to be useful to the player and adjust accordingly.
Small point about throwing knives: While a staple of the rogue’s combat technique, throwing knives in the real world are much less useful than are portrayed in media. They are much more useful to distract opponents rather than killing or crippling them outright, as even with a lot of practice they rarely end up in exactly the position to stick into foes and do enough damage. Knives or darts with effects are much more useful to rogues than simply dealing damage. Things like a short stun, distracting a foe while concealed or attracting attention from specific targets are all things that small thrown objects are good for. Something to think about for a more realistic or tactical set of mechanics.