Roger Waters has always been full of himself. He destroyed the best thing he was ever part of, which was Pink Floyd. He was a dick and always fought with David Gilmour and left because he thought he was the star. Reality proved otherwise.
Um. Yeah. Tell me the most awesome song that Floyd did after Waters left.
You really can't. The produced three Studio albums since getting back together in 1986, one of which was just taking outtakes of Rick Wright playing various keyboards. (I really don't know why they even did it.)
Momentary Lapse of Reason was Gilmore hiring a bunch of writers and saying, "Write something like Roger would write" and getting nowhere near the mark.
Division Bell was a little better, but nowhere near as great as their classics of the 70's.
Meanwhile, Waters did three Solo Albums, which are pretty darned good. He also did an opera about the French Revolution, not sure what he was thinking there.
Sort of, the differences really started to manifest around the time of Animals and Wish You Were Here. Then came The Wall, the firing of Rick Wright, and the financial near ruin caused by their (mis)management and expenses of The Wall tour.
Actually, it was more along the lines of differences in vision. Prior to Dark Side, they kind of equally divided songwriting duties, which is why you have some albums that are pretty uneven, such as
Meddle and
Atom Heart Mother. Waters took over Lyric Writing on Dark Side and afterwards, and the difference showed.
The real split came with The Final Cut (an album that is highly under-rated. It was an indictment of war and politics of the time. Gilmour just wanted to do pop albums and make money.