An important part to a mechanic feeling fair is the feeling that you (the target) can do something about what's happening. I.e. any mechanic (Ness side special) must have some sort of counterplay.
It's a design decision on whether that counterplay is specific or more general - Super Smash Brothers prefers more general counterplay mechanics in dodging and shield to avoid attacks, and falloff to make spamming a single mechanic less effective (as you use an ability more, it does less damage; as you dodge more, dodges provide less invincibility, lock you out for longer, etc). To continue the original example, there are a variety of general counterplay maneuvers to a player using Ness to spam side special and followup with a smash later (in order from general to specific):
- As Ness uses side special, it does less and less damage, so the use is less punishing (every ability has this same mechanic)
- The ability has an animation (as all abilities), which puts a window of vulnerability on Ness (every ability has this same mechanic)
- Side special is dodge-able, though its persistence makes it less good to block. (Mostly generic counterplay)
- Side special is a projectile, so any projectile reflect or absorb abilities will stop it (generic to any projectiles)
So, more generally - to make a fighting roster actually fair, you must include counterplay to any given mechanic. Not necessarily perfect counterplay (all of the above still rely on the receiver being "good enough" to execute on the counterplay strategies), but some counterplay.
To make a roster feel fair, you must make counterplay strategies accessible. It's one thing to have dodging/blocking/projectile reflection in the game, it's another thing for those mechanics to be available. If you can dodge an ability but the game never tells you that "dodge" is an action (or how to do it), then it's not an accessible counterplay mechanic. There are a variety of ways to make mechanics accessible, for example:
- A tutorial can go a long way in showing players mechanics and how to use them
- Help pages to refresh memory on what mechanics exist without having to replay the tutorial and learning how to walk again. A tutorial that's setup in steps that are each individually replayable can assist this as well.
- i.e. a help page detailing "this is a dodge, this is what it does and how to use it [with a short video to help players recognize times they've dodged or enemies have dodged]", and then a playable exercise to show off dodging and give specific practice
- Periodic random tips noting counterplay mechanics, or the ins-and-outs of them can be really helpful
- A tip saying "dodges exist" isn't great (though depending on genre and target audience, a tip saying "If you're being hit too much, try dodging!" could go over well)
- A tip mentioning that "Y character's X ability can't be dodged, but blocks are effective!" reminds the player to dodge, reminds the player to block, and gives the player insight into how they should be countering another specific instance.
- Even using the "show don't tell" method can work well with this - if you have AI's make full use of the counterplay mechanics you expose, that can help players realize what those are and how to use them (you start realizing how good dodging can be if you're doing something and the enemy AI is dodging it constantly).
