I actually don't mind these challenges that have you kill bosses in certain ways, the ones that annoy are more like "get all the x from this league, and btw some of these are super rare, or require a bunch of RNG to even spawn and more RNG to get" and shit like that. In incursion, it was shit like upgrading all the rooms to 3(which wasn't hard, just purely RNG based, and a bitch at times) or the worst offender, getting all kinds of results from the fairly rare rooms, like getting all 3 types of gem corruption from the lvl 3 gem corruption room. That shit was super cancer.
But yes generally you can remove the 4 worst out of the bunch and end with ok challenges for the 36 others, but a lot require a fuckton of time and/or currency to get and it still takes quite an effort to do them, especially if you're not amassing wealth. Mind you I had a bunch of maps I dumped in the guild stash back in Incursion, so selling them I could have maybe done most of the challenges up to 36, maybe. I forgot exactly which ones were too bullshit.
We'll see maybe I'll feel like doing this league, the wings do look pretty good for once, generally I don't do 36 both because it's annoying but also because the rewards aren't worth the trouble.
Need to warp a couple days ahead to see the patch notes first though.