Yeah, when I bought my first real Zildjian cymbol it came with a book depicting the set ups of many famous drummers. In it were also very short bio type write ups and under Neil's he listed his early influences as Michael Giles (Giles Giles and Fripp/King Crimson, etc) Phil Collins and Bill Bruford. There might have been others mentioned but those were the ones that stuck out. It was the first time I ever heard of Mr. Giles. He is now one of my favorite drummers.
Again, I think Geddy and Neil were obviously wanting a more progressive direction. I'm not exactly sure about Alex but his later work (La Villa in particular) shows that he picked up on the idea big time at least.