Great point about the stagnation. It's just human nature. Same with the depth. If you have 10 runners going 2:20, they will push themselves and a few will break through to 2:17 to be the winners. Right now, we're more at the point of having 10 runners going 2:25 so they just have to push to 2:22 to win. Pack strength will force the winners to run faster.
I like the idea of taking nationality out of the WC and OG and using WMM events as qualifiers. Unfortunately, nationality has become such a part of those events that I don't see the possibility of it ever happening. When we think about it, though, what does nationality mean? How many Olympians who reside in Boulder or Flagstaff or similar places in Europe or Asia run for nations other than those they live in?