Git couldn't really handle all the binary assets, and the artists couldn't really handle git, so it made sense. When we switched, it also took a long time before the programmers could really handle git too, fwiw.
I've long said I'd love to see something that's as nice a GUI as p4v, but with git under the hood. I haven't yet seen a git GUI that even approaches now nice p4v is, and git on the command line, once you learn it, is the best interface to git hands down.
I can't tell, but does gitless look like it could make a simpler gui to anyone else? I love the idea of gitless, I'll have to try it, but I get the sense that I'd end up needing to switch to git for some things.