I found them tremendously cheesy even back then, and I was pretty young when the first movie came out... It always felt like one more reminder that WE ARE WATCHING A SUPERHERO MOVIE, almost like the opening credits to a cartoon. First Class got it right, diving right into the story with the very first shot. In doing that, it felt more "realistic" (as strange as it sounds). Singer's opening always felt like a big disclaimer that we needed to suspend disbelief for the next 2 hours. Which I suppose made sense at a time before superhero movies were commonplace and treated like "normal" or even "Oscar snubbed" films.
But times have changed, and so have superhero movies. So hopefully Singer won't be using those god-awful opening sequences again. Regardless of how good the movie may turn out to be, starting with that stupid thing would bring down the entire movie in my eyes. It's been more than 10 years since the first X-Men movie, and reusing those credits would be a sign to me that he hasn't evolved as a director at all.