It was just too obvious in the last scene that Mike was going to get it(and it was something that i feel most people were anticipating way before then).
The Mike i know would've said "No Walt, i don't trust you, stay there." but for whatever reason he trusted Walt with that extremely important task. I thought that Jesse would've brought the bag, Mike would disappear, and then Walt would kill Jesse at some point which would lead Mike to risk it all and hunt down Walt for revenge.
Whatever though, still a great show!