It is interesting, and perhaps somewhat surprising, that there is a sub-set of distance fans who would prefer that all distance races have ideal/near-ideal conditions. Like others, I find it easy to look at it the other way, as in, "Don't we already have enough of those kind of races (London, Berlin, Boston, Chicago, New York, etc.)?" I'll always remember thinking that the World XC Championships being in hot coastal Kenya many years ago made it much more interesting (including Bekele calling it quits mid-race). But, of course, there were plenty who complained.
And as someone else mentioned, it's not like the warm and/or hilly marathons necessarily select clearly slower-under-ideal-circumstances people for all of the top spots. Kipchoge obviously won quite easily. And on the women's side, the WR holder was second, and I believe that the final pack of 5 had PRs of 2:14, 2x 2:17, 2:19, and.....Molly at 2:25(!). And would I want extreme conditions if it meant that the WHOLE lead pack was 2:25er's? No. But if it means that ONE (or a few) of them has a chance - a chance that wouldn't occur when it's 50 and cloudy in Berlin - that's pretty cool.