First Class feels so much more in synch with the Singer-films and his style that, I at least, had the feeling he directed it.
I don't see how you can make that statement. The Singer X-films are ponderous, allegory-ridden angst fests where the characters spend as much if not more time navel-gazing about the Mutant Question as they do engaging in feats of super daring-do.
The fight staging is slow and blocky and oh-so stagey. "Ok, first two mutants up! Mutant 1 do your power. Mutant 2 do your power. Cut. Ok, next two mutants up..."
And they hideously underpowers 99% of his characters. Magneto didn't even get to BE Magneto in any meaningful way until III.
This was part of his "keep it 'real'" philosophy, whether it was self-developed by Singer or imposed by the suits in the front office. The first three films acted as if they were either ashamed or frightened about their genre.
It wasn't until FC came out that the franchise finally
"embraced the spandex" and became a proper super-hero franchise entry.
First 3 vs First Class is the creative difference between night and day.