I don't think they should be lumped in the same category as mechanics that just get more potent the longer you sit on them/the more you're losing like X Factor and SF4's revenge meter. There's no real strategy or decision making there beyond deciding when to use this superfluous resource for big damage.
xf isn't dumb because there is no strategy to it's usage, don't miss the point on why it's bad please because boy howdy it is bad
it's more like it simplifies the game for the player using it after they've entered into a scenario where they're at advantage when they're losing and using it and those scenarios are extremely common given the extreme strategic versatility of actually using the initial canceling and time stopping aspect of it.
after that it's used as a way to exacerbate underlying problems with game to the losing player's massive advantage by turning the game into guess city with low punishment for commitment on things because of the extreme speed and damage boost granted
i'm not really qualified to say how much ultras are like that though. they might be in a similar situation.
While meter gain, bursts and clashes can be controlled by the winning player if they make the decision to. X Factor essentially exists outside of the game. There's no way to build it, deny it or conserve it. You can't even really punish it.
you can definitely bait and punish xfcing blocked stuff and an integral part of the incoming mixup on the last character when they've put themselves in a situation where they don't have time or resources to set up the incoming mega dumb mixup is to bait XFCing with meaty normal or blockstrings you normally would not use. just a nitpick 'cuz that's not entirely true. (i'm just nitpicking to add onto the 'the actual initial usage part can be strategically fine but it's what happens after that matters the most for comeback mechanics' argument.)
comeback mechanics aren't necessarily inherently bad by any means- it depends on how the game is designed. nothing too harmful if the mechanic and game go together well to create a better pace with strong strategic choices throughout the match.
really, anything that actively simplifies the game after it's usage really shouldn't exist. the trait of player manageability seems like it'd go a long way for determining whether the mechanic does that or not, but at the same time my brain keeps going to tvc bursts as a possible counter-example since on a surface level it seems to have that trait while also being like one of the most reviled mechanics i've ever seen