I will keep my response brief. First, your last analogy between the Bubble Shield and Armor Lock has no validity in my view. The shield does not make you indestructible, emit an EMP, destroy vehicles, denature the blast of a stuck on sticky. deflect rockets back at players, etc, etc. The bubble shield can be entered by another player to continue a fight, vehicles can pass through it and it is available to any player that happens across it.
With that said, I do agree with some of your points, but to me what set Halo apart from the other games was the "mild" target lock that exists. The maps were better, on whole, in the original Halo titles to me and had an overall better feel. I will, or we will, never know what the current maps of Reach may have felt like if not clouded by all the other factors. I honestly believe there is no way AA's will be seen again. Like you, I expect change and advancement of the original series and feel there were enough unliked changes that drove away or alienated fans. Nice OP to bring forward another good discussion.