Re: What was wrong with the current trilogy?
X-Men was a perfect example at adapting the fantastical comic book adventures of the X-Men into a real life setting without compromising too much, making their uniforms all leather black made more sense than colorful vibrant colored spandex and the performances were done in serious manner.
X-Men 2 was a perfect sequel expanding on the plotlines from the first movie into a more satisfying action pic without shoving every new mutant on screen.
X-Men 3 while still good shouldn't have killed off 3 of the major characters, the story felt rushed with too many characters not getting enough screen time coupled with a shorter runtime for what was intended as a grand epic finale didn't really feel satisfying but having Magneto retain a hint of his powers at the end was a clever idea, too bad further sequels will never expound on that.
Self-contained stories part of a larger story is where its at. Not this writing for the trade nonsense. If you're going to write for the trade, don't release it in individual issues. Just release the trade.