What I personally think 343 should do it to keep the armor on the credit system. But they need to make it so you earn more that what Reach offers each day. I would also suspect for the ranking system to be run right back where Halo 3 left off, the 1 - 50 system. Remember the trueskill system too. And 343, please do not make six maps on a single maps using forge. Make them like Halo 3, fun to look around, diverse, and fun to play on.
I agree with you Monster on the Armor and the credit system. To each persons decorated armor and levels is more entertaining to me rather than seeing the same armor. Kind of sucks to me, rather see more options and more creations from the fans of Halo.