What about the Reaper bunker strategy? Playing as Protoss it's a real diffcult one to face. Probes just don't hit the SCV enough to stop it from building the bunker, with the 2 walls used anyway (and the reaper attacking probes at the same time)... The only counter that seems to work is a real early scout, or to play as zerg. I hear they're increasing the build time of each a bit? though I havn't actually searched it up. All I can say is I have a friend who is very good at it and has made it to diamond league and still wins most of his matches just by doing it.. Myself I'm more of a typical player just learning the game, getting better though :P my RL friends often seem to let me down a bit, I usually top the team.