Yeah I can see that. Watching the old X-Men is kind of janky, yeah, but you can tell they really studied the comics when making it. It feels like a comic book in action.
For 97 the stills make it look like “a modern old X-Men cartoon” which is great! But the final effect comes off as just fine. I think it’s because it looks like it’s been mastered on a computer with fully cleaned up lines and tweening between frames.