The only reason I missed the mc in halo reach was that they pretty much fucked up halo reach, the story was boring, the chars were pointless, the outcome was obvious, I could have made the story much more interesting, but then again I wouldn't have done a damn prequel, those are the dry hump of sequels. They didn't have to totally ignore the mc in reach, they could easily have had him show up and not been the main focus, no one in the game even mentioned him, he only showed up at the end if you held the control stick to the right when it showed the inside of the pillar of autumn, you could easily have had the chars mention something about an upgrade program that John was chosen for, hell they could have worked him into some of the earlier levels before he went in for upgrades.
But I would've have done a game about reach at all, I would have continued the story with the arbitor as a big focus, maybe throw in a few upgraded hell jumpers as something as they seek to put down the rest of the covenant, the cov just lost one of their giant space platform things, they still have homeworlds all over the place and those will probably need to be either taken out or pacified in some way.