Hugh was contracted to do X1 and X2. Every film since then, Hugh has done for excitement and love of the character. And of course, while making the movie, everybody is doing their best to make it the best...no one sets out to make a bad movie or even a crappy movie.
A lot of the cast said they thought X3 was going to be the best one yet. Is it on par with X2...many would say no. But X3 is far from the travesty many make it out to be. I'm actually watching it right now and realized how much I still like the movie.
And Hugh was excited about Origins. He thought, while filming it, they were doing justice to the character. Once he viewed the final product, I'm sure he had some bad feelings. But as others have said, he's a professional.
So honestly, if Hugh's still like playing the character and the story/script is exciting enough for him, he'll be back.