It isn't really fair to compare X1 & X2 to current movies either. Sure, compare it to Spiderman 2 or even Dark Knight, but comparing it to DOFP, Avengers, etc. is being unfair. They were very good (if not great) for the time they came out. Sure, they could have been even better, but compared to almost everything else we'd had for the past decade of similar background (I wouldn't include a movie like Blade here, even though I loved it, as it wasn't really so much a superhero movie), they were both damn good. I've watched them both a couple of times since, and while they aren't my favorite movies ever, I'm not sorry I watched them either.
Ten to twenty years from now they might have movies that just blow something like Avengers out of the water...but that isn't going to mean that suddenly Avengers is a bad movie. It's great right now, when it is fairly current, just like X1 & X2 were when they were current. Or at least very good.