It's not that Singer is a bad director, but I was finally happy to see what Vaughn did with First Class, being the first X-Men movie I really really liked. I thought the franchise was reborn and redeemed. Problem with Singer is sometimes he's arrogant with his decisions and has a limited vision. I mean, many things were good intentions in Superman Returns (a film I do not hate), but a lot didn't worked to keep the franchise alive (Superman's son, Kate Bosworth, Superman horrible costume), things he wanted to do just for the sake of his idea of impressing fans, and ended as bad baggage for the film. I don't know if I'm alone here, but mixing the old cast with the new one, doesn't sound so great to me. I never loved many of Singer's casting choices for his X-Men movies. Jack, the Giant Killer already looks like a dumb effort to me in the trailers, and I fear Fox may regret the decision to needlessly turn this franchise back on its steps. Hope Singer proves me wrong.