I thought it will be an overhyped nostalgia train. I was wrong.
Firstly, no, it did not bother me that they "flattened" Rogue. Because it was not that noticeable really, I'd say she was mostly same as in original series, unless you compare her to just a few very specific frames from back then. Besides, it really does not matter for the plot here.
Secondly, it was a good idea for me to rewatch original first. Watching them together really shows how far modern TV story-telling has come. And comics story-telling as well, since they did put in a few arcs from more modern comics (or something similar, at least). The story structure alone is leaps and bounds away. Original show did not have stories (plural!) spanning over the whole season and converging in the finale. They were mostly standalone, even those 2-part or 4-part arcs.
In the new season, though, Marvel did what I liked them for when I was reading comics during the times of "Avengers Disassembled" and up-to some reboot of the major series, was it "Brand New Day"? And that was "planning". Same thing that made the MCU's Infinity Saga work so well: there was clear intention even behind seemingly small things. The details were not added just for the sake of them being there, they were part of the story, part of the narrative.
Yes, narrative is still "comic book like" in some places. They are not going too deep, they are not "too mature" with some things (although there was some blood here, at least), but it felt thought-out. This thoughtfulness also made characters feel more natural, more believable. Heck, they even started working as actual team, having "synergy" on the battlefield, combining their unique skills, which was very rare in original. And this synergy also looks good. Aside from questionable design of some things (Magneto's face, at least).
It was not perfect, though. Bishop was somehow stuck in the past with no clear explanation. Jean was pregnant, although I am sure it was not the case at the end of the original. Jubilee was 15 in original, now she is 18, but it was said that a year has passed, although at some other point it was suggested that only a few months passed. Nightcrawler was suddenly closer to his interpretation in X-Men: Evolution, which I did like, but it did not fit the character from original.
Overall, though... I do want to see the 2nd season. If they will be able to keep the quality at least on par with this season. And if at some point they will do "House of M" and "Decimation", that would be even better. Unlikely with the current timeline, though.