This is one of those subjects that is bound to get me fired up for years to come b/c I'm too close to the issue. Some thoughts, which hopefully won't turn into too much of a rant:
-We're doing a magnificent job of letting the defense industrial cart get in front of the strategy horse. If we're going to pivot to Asia, avoid major land conflict, and all the other things that come from the last decade of conflict (what I lovingly refer to as most of my adult professional life) then why do we need to have a vehicle that is the perfect apex of technology to win against the last war(s) threats. Quite frankly none of the candidates are a revolutionary leap beyond the existing MRAP and MATV family so why invest in them at all?
-The HMMWV performed magnificently in roles it was never supposed to in numbers well beyond what the task organization of any element of our armed service were supposed to have. For fans of history the HMMWV is easily akin to the German Panzer Mk IV; none of the glory of the Panther or Tiger but it was the workhorse day in/day out for the bulk of the real fighting that took place (at least in Iraq) and when you reached the pinnacle of its up-armoring it was a decent truck that kept a lot of people alive. I loved mine:
Would it defeat bottom attack IEDs or the best in shaped charges? Nope, but the harsh answer to that is something that people don't like to hear:
-Change your tactics. Walk more, at night...like this
You don't get IED'd that much when you are on foot instead of staring through your bulletproof glass. Moreover the guy you're fighting wears flip flops...all that body armor isn't that impressive and when you are acting like infantry you look like an overweight cop chasing a crackhead. But I'm biased. IED's are a symptom of a conflict, not the cause. Attack the motivations of those picking up arms and you stop IEDs.
Some other food for thought:
-None of these vehicles float and all of them weigh a lot. Meaning they don't fit well inside amphibious shipping, so they'll require black bottom boats to get them anywhere in significant numbers-which further means we have to own a port in a conflict zone or take FOREVER to build up combat power. The weight issue means because they are so heavy flying them in is painful and VERY expensive.
I guess my bottom line is we need to think of what we really intend to do in terms of strategy, and doctrine, and then build equipment that is effective in that arena. In the meantime HMMWVs would work fine in most conflicts we face until it matures threat-wise into a real IED environment (Syria, for example, has been in a civil war for a year and it took almost that long for the IED threat to actually emerge).
I'll end my rant for now lest I go further off the deep end...