I always saw kaiten itself AS the alternative use case for Kenki, which now really has no other use case.

Also bros come on with the "why not ask for something better?" Stuff. This is Square Enix. They don't give take something away and give back "something better." They take something away and best case scenario give it back in a mangled form. MCH ammo? Gone. MCH heat? Basically gone especially compared to what it was.

Dark Arts? Energy Drain? Heavy Thrust? Summoner as a whole?

Nobody is gonna ask for "something better than kaiten" because just getting kaiten back itself would be a miracle at this point. Also most of people's suggestions for replacements for kaiten either require overhauls for the job in a positive direction (ha!) Or overhauls of the entire game's combat system (Hahahaha!) And some only just...do the same thing Kaiten did in the first place which was make you think twice about kenki expenditure, and do nothing to tie kenki to iaijutsu in the same way that kaiten did.

So I mean sure, ask for better. I guess. I'm pretty thoroughly meteion-pilled though, and know that even just asking for kaiten back unharmed is asking for a miracle while winning powerball while getting hit by lightning.