I only play on US servers, so I'm used to faster speeds. But even with that, I think slower speeds make the game more fun. The faster it is, the better spam works, and that's no fun.
With slower speeds, especially with large numbers of players, teamwork and tactics become more important. Faster speeds would be better for small pop servers where there isn't as much room for large scale teamwork and tactics and instead is more of a test of quick reflex combat skill.