A lot of people talk about how good Desi Linden's tactics are. I certainly agree, but I feel today she was so strong and won by so much that there wasn't a race (in those conditions) that she would have lost. She has convinced me that in those highly unusual conditions, she is likely the best marathoner in the world.
The men's race was different. Kawauchi only went by Kirui very late, and that was after a lot of fast and uneven running early on. I don't think Yuki's win was guaranteed by any means; I think he won it partly by talent, partly by toughness, but partly by tactics.
Here's my thought about suicidal-seeming moves: if you make your competition run YOUR race, it's not a stupid move. So setting a moderately quick even pace for 12 laps of a 5k: bad. Turning the race into a positive/negative split affair when that's your jam: good.
The commentators talked about the fast start like it was just Yuki running that pace, but everyone in the front pack did close to a 15-minute first 5k in howling gales down quad-pounding hills. And some of them broke the wind as much as Yuki did. All of those guys "had" to run Yuki's race, where he's very well equipped to do well. That's the Japanese style: fast start, no concern for the weather, and in Yuki's case, a monster finish. In retrospect, a fast-finishing, hot-weather runner like Rupp had no chance.
Similarly, what Wanjiru did in Beijing is what he was singularly good at: starting out way too fast in hot conditions, and then dying a less miserable death than everybody else. To beat him you've either got to run an even-paced 2:06 from multiple minutes back, which no top contender would willingly do, or you've got to run his race.
In a way, both of these moves *were* suicidal, but as long as everyone in the race has to do the same thing, you're not giving up much. So maybe we can judge these sort of moves a little differently in the future:
1) How much does this race style suit the runner who caused it?
2) How much work did that runner have to do BEYOND what the other runners did?
What a day of running!