I realise everyone has a bias and SC2 is probably unable to be properly balanced.
Btw you're very wrong, I have two EU accounts and 1 US. 1 for each race and i'm a Masters Toss/Terran and a Diamond Zerg. When I play the playhem daily which I do most days I roll Random.
My bias is not from just being raped repeatedly as Terran by Protoss AOE, it's what I know from playing both races and the huge problem in TvP is that past the 10minute mark the army composition for Terran has to be MMM(With G and/or V).
A 1/1/1 is simple to hold as Protoss because it's become so common, it's the 2rax situation currently happening. When something is trending it becomes easier to stop because more people do it and more ways to counter it or nullify it are being discussed or put into play.
Either way the 111 or any variation is shutdown by a robo which should be placed somewhere between your 1st and 4th gateway.
I laughed when you mentioned Muta Harass and not Infestors XD AOE Imba