I can see the reason why people have the fairly absurd kneejerk reactions as all the new characters are kind of breaking the mold of what makes a smash character, pass 2 especially more so than pass 1 but the thing to keep in mind is these gimmicks usually come into effect when the characters are at a disadvantage, and have other weaknesses to help circumvent the mechanic being a full on get out of jail free card. Joker has to take at least some damage before he uses Arsene even if you want to use Down B, Hero's mana is really only a detriment that puts a cap on how much he can use his spells, Terry needs to hit a pretty high percent before using his supers and even then they are really slow so they're pretty balanced, Steve literally needs to camp to be able to do anything otherwise he's weaker than even an aerial only Mac, Sephiroth has an absurdly light weight, large frame and poor frame data meaning even with the one wing boosts he still is just as prone to KOs as ever, and Kazuya has trouble approaching due to his sluggish speed and is forced to do so or else he loses rage.
It isn't straight up you press a button and get better like Zelda and Sheik with the only detriment being the occasional punish, they have legitimate drawbacks that prevent them from being broken despite making the characters better in pretty much every way when capitalized upon.
Ultimately, I think it just comes down to the fact that gimmicks as a whole were largely abstract from smash until 4 started to add them to most of the characters to make them more unique and how Ultimate DLC just ran with it and started adding a bunch of stuff we've flat out never really seen before in smash, and pass 2 went to ridiculous lengths. The most gimmicky character in pass 1 were Terry and Hero but fi we're discounting the latter as the largest mechanics there were reliant on RNG, the most Terry had was a back special and supers with normal cancelling, some command normals and the occasional tap/held special. Pass 2 however isn't settling on one mechanic for every character however and all the mechanics those characters are getting are really unique in and of themselves despite all being part of one character. Min Min's arms function like disjointed Megaman lemons, except she can throw only two out at a time but in return can throw them out out at the same time on different sides, can curve them, perform this even whilst crouching, and even use them as a smash input, grounded or airborne. She's even able to switch the currently equipped special arm which all have completely functions themselves and she's able to power up her dragon when using a throw, all whilst still maintaining her normal kick moves. Steve can place blocks, mine from the stage itself, boost his weapons power and durability in order to make sure they don't break with a background element etc, Sephiroth has a form which factors in earlier at different specials and a bunch of specialized interactions with his sword normals, a bunch of sweetspots and a bunch of specials which are really unique themselves, Pyra and Mythra are two in one with mechanics of their own and Kazuya has completely unique attacks and properties only he can really call his own, even more so than Terry and the SF guys and Rage on top of all that. They seem to be deliberately putting emphasis on uniqueness in this pass especially, and approaching really abstract concepts which aren't present in Ultimate and since they are so detached from even the likes of Bayonetta and Ryu, who were the gimmickiest of smash 4 dlc, they completely break the mold even they set so it's understandable why people will yell busted even when they are surprisingly balanced for characters of their kind.