Growing up I adored Roger Waters. But over the years, I have soured on him. Pink Floyd was at their peak when Waters was just a contributor like the rest of the band, and not a total control freak.
Here's my take on Roger and Dave:
The ambitious Roger was a good experimental musician, a good lyricist, and a decent melody writer. But he wasn't much of a bass player or vocalist.
The easygoing Gilmour was a good fundamental musician, a decent melody writer, a good vocalist, and an excellent guitar player (and not a bad bass player either judging by his work on "Pigs"). But he was a poor lyricist.
They complemented each other well. The best Pink Floyd albums, in my opinion, are combination efforts where these two worked together to fill in the rough edges from the other, and got occasional contributions from Rick and Nick. This coordination peaked on Dark Side and Wish You Were here, and fell apart on The Wall, which was too unbalanced towards Waters. The Final Cut can hardly even be called a Pink Floyd album.