This might be a dumb question; I actually don't own SC2, so what experience I have is playing friends' accounts. But my friend has been playing on Diamond + Platinum, and so far he seems to be unopposed by 4 warp gate rush. Which is basically 4 warp gates + proxy pylon within 6 minutes, and sending in 3 zealots 3 stalkers.
Anyone who tries to tech up simply gets destroyed, because he has no units by the time the warp gets there. Is it because he hasn't been encountering anyone who is actually good?
And what are good counters to this, if I ever end up buying SC2 and playing against him?
I feel like this can't actually be a competitive build, because it doesn't seem to be the win-every-time strategy in professional games.
edit: I guess the more specific question I am asking is, "What are essential/crucial weaknesses in this build? (in general) In particular, the weaknesses that prevent it from being the end-all build"