Max. Suit has always given you full run capabilities. You do not need AE II+ (which removes the armor mobility decrease) Max. Suit automatically gives you full mobility capabilities. As far as I know, it has been that way since day 1.
That's odd. I distinctly remember numerous times that I activated max. suit and I was moving at a slow pace of using regular armor. I rarely use AE for it to play a part in my killstreak. Guess I'll try make a mental note next time I earn the killstreak.
I find it to be a bit glitchy sometimes, and I'll activate it and move at a slower pace, so I would agree with that statement. However, I have over 200 activations of Max. Suit, and I can say with confidence that it almost always gives you full mobility. I would say at least 90% of the time. I would chalk up the times it doesn't to just part of that buggy Crysis 2 problems.
It's not a bug. If you activate Max Suit with armour on it will be slow like normal. If you activate it with cloak or power on it's fast. Too bad max suit svckS now.

They REALLY need to make it good again.
Anyway the MK60's only hotfix difference was it's recoil, which decreased. So they only explanation I have for you is that you aren't getting as many headshots anymore so it feels less powerful. Personnally I think it's still super-good.