Some random research after messing around with a library that parses SC2 replays:
This is based on 270 replays from GSL Season 3 last year, the WCS Finals, and GSL/SSL Season 1 of this year; each bar is a set of 30 games.
I'm mostly interested in comparing this against the replays that come out for season 2, following the swarm host nerf, both to see:
a.) how general game length changes in ZvT/ZvP
b.) if Zerg's lategame winrate drops even farther, and is perhaps made up for with an increase in early/midgame wins