What you’re asking for is not new, although it would be common sense to change it to that, 343 is too stupid and/or arrogant to change their magnificently horrible control schemes for this game. No matter how good the game is (I have high hopes for it) a terrible control scheme will negate all of their work.
X for Reload and B for Melee is SENSICAL, a good mix of all the Halo games.
LB and RB for the AA’s and Sprint would definitely make sense, and I really hope they decide to fix it, especially since nearly everyone that plays games enough to go on a message board to talk about them has acknowledged how bad they are.