Potential is one thing. Execution is another. People take for granted how entirely wrong the X-Men universe could have been portrayed onscreen. You say X-Men had the most potential, but it also had the most potential to fail.
Save for Stewart, those people were not box office draws before X-Men (if you even want to call him that). If anything, they became box office draws after X-Men, and Hugh Jackman because of X-Men.
That's not surprising. The X-Men come from the comic books, in which they've become over-powered, and the movie has more superheroes in it than most comic book movies do today and on a relatively small budget.
It's always easy to say, it could have been worse. That's just as easy as saying it could have been better. That's true for most circumstances. X1 clearly did not fail, but it's very underwhelming in my opinion. X2 is what I expected for X1, if that makes sense. I can appreciate X1 for what it is, but I wasn't satisfied.
For your second response, that's fair. My point is, if budget is supposedly one of the limiting factors of X1...I'm pretty sure there were less expensive actors/actresses available with talent. Correct me if I'm wrong, but even the actor playing Toad was from Star Wars Episode 1? Sabretooth actor was wrestling star? Halle Berry was one of the prominent black actresses at the time? Patrick Stewart and previous Star Trek affiliation? Rebecca was a super model?
Who do you think received the higher salary? X1's mystique or XFC's mystique? Serious question.
With that said, is it really hard to not see that maybe the cast selection was intended to pull some movie goers?
For your third response, if you think the X-Men's comic iterations have become too powerful, that's fair. I wonder what you think of meta-humans in the DC Universe then?
I believe another poster mentioned Angela Bassett for the role of Storm, which is who I originally envisioned for the role of Storm...but her age would have caused her to stand out among the cast and despite her great talent...she has never received the recognition Halle Berry has received...even though she has played great roles.