I sadly have not played 4 or 5. I don't know why. I think I read something about 4 when it first came out and it turned me off of it. But for the life of me I have no idea what that was.
I actually like the slow movement of the mechs. Something about them felt so much more real unlike something like Gundam. I'm very excited for 6 but yes I fear it will be to quick.