I'm rewatching this series for the first time since I was in primary school. Some scattered thoughts I have on the first five or so episodes: Xavier's voice acting I initially found a bit too nebbish and slightly sinister-sounding, but I've quickly gotten used to it.
Wolverine and Magneto's characterisations feel overbearingly cliche and paper-thin. Wolverine has grown on me a little already, but with such brief appearances to go on, Magneto especially feels a bit disappointingly two-dimensional in comparison to the slightly more complex characterisation I've grown more used to with the movies. Any attempts at nuance with the character feel forced.
I like the art style but sometimes I feel like I'm watching a bunch of action figures duke it out, especially with the slightly shoddy animation that comes with a first series. The Sentinels are perfectly portrayed and do a lot of the heavy lifting in making it feel like a very oppressive, semi-dystopian world. The first two episodes felt the darkest on account of their presence, and with their absence, the show doesn't feel quite as dark as it initially did.