I don't think there has ever been a team left out that was a legitimate national title contender. And until that happens, there isn't really anything to complain about. And I just don't see that happening until there are fewer than 3 Pool Cs left.
Of course by definition you can't know this though,right? We have had 1, two loss teams make it to the semi's in the last 10 years. Both of those were the "last team in". Wheaton in 2008 was a 7 or 8 seed in their bracket. North Central was the undefeated 1 seed if I remember. UMU was the East #1, Wheaton played Wabash, Trine and Franklin all on the road before losing to UMU in the semi's. In 2010 Bethel was a 9-1 Pool C and seeded #6. They went on the road and beat #3 Wartburg, #2 Wheaton and #1 St Thomas before losing @ UMU. I think it's a matter of time until we see a Pool C National Champion. It seems more likely to happen than not.
Again, I have no beef with the number of Pool C's. I think the criteria are somewhat random and nonsensical.
Wheaton in 2008 was beaten by 21 points in the end and were down 31-10 at the half. They did have a charmed run, but it came to a close a bit flat. Same with Bethel's 20 point 2010 loss where they were down 34-7 at the end of the third. I have no problem with a Pool C champion. I just don't think we've ever excluded a team that could really win it. Go on a run? Sure. A couple teams have. SJF was the last team in the field in either 2011 or 2013 and did a nice run. Before losing by 20+ both times also to UMHB.
But you saying "we don't know" is the same criteria I'd use about limiting Pool As. We don't know, but the As earned it. Now as for a beef about the criteria, I just don't care that much. Regardless of what criteria you use, someone will always have a beef. Again, that last Pool C or the first one left out? Just not really a threat. A better threat than some teams that are in, for sure, but not a threat to win it all. There are only 5 or 6 teams, at most, in DIII that can win it all in any given season. Every one of them has made the field. Now there might be 15 teams that could get to the semis on a good run, and one of those maybe gets left out, but that just doesn't interest me all that much.