Zerg game-play is the same? Disappointing but I kinda doubt it. From what I've seen you have to aim for 40 minute games, where is WoL zerg games aimed for the 15 minute mark (in ladder, obviously in tourneys if they missed that mark then they are off to the bl/inf build).
Maybe try dropping at other locations or further away from the basecannon? Eg dropping 6 range behind mineral line, or going for pylon snipes or tech snipes or going for an expo.
Counter oracle harass with missile turrets? Once you scout the tech just drop a turret - or two at each mineral line and it should be fine.
What's your average game time for zerg against the other three? Is standard zerg still 11 minute roaches off 3 base? I keep rolling this build blind on ladder (scouting at 6 minutes, so not completely blind) and I rock up against 5 mutalisks, or a handful of hellions and MMM, or a handful of stalkers (or dts...). It seems people in plat are just lazy... in WoL T open hellions vs Z, Z opens 14 pool to mutas (
) and P just play their usual stalker/sentry/coli or one of their many many cheeses. Are you using roach max? Interested as to how it does vs widow mines and MS core