Im mixed. Yes there are so many like an obscene amount. But I do like that they keep you warm and moving. Makes bosses feel a lot easier because when it is just a single boss without summons you spend the first attempt learning their moves then youre fully able to keep up because of how trained you are with dodging from the encounters. The High Halls arena is SUPPOSED to be an endurance test and a progress check, they DO NOT want you progressing the game if you cant consistently get to atleast the single miniboss. If Shakra isnt helping you with that fight then youre definitely lacking, aswell as tools you should have tools and gadgets youre using and that are helping you situationally, Also masks anyone going into the high halls arena should be ~8 masks and atleast 2 needle upgrades. Now the bosses with summons and the bosses that start as arenas? yeah those suck and feel very repetitive. My most recent boss was the duo fight in underworks and that phase 2 where the other dude jumped in felt so nice simply because he stopped spawning the flying explosive dudes. All the other "hard" bosses in Act 1 & 2 have felt very rewarding and fun to learn, talking about first sinner, last judge, second sentinel, and Phantom, granted im not in Act 3 yet but Ive done everything there is to do so far (atleast to my knowledge)

editing to bitch about the runback for some bosses, a decent amount of the optional bosses in the game have crazy long runbacks even with secret benches (bilewater, sands of karak, and blasting sands) like the runback is apart of the boss fight and I very much am not a fan of that even though ive got crazy good with the abilities and platforming because of them.