Is ZvT imbalanced? I doubt it.
There is a lot of talk going around about this MU being imbalanced, that it's Terran favored. Idra, Sheth, Dimaga, MasterAsia, and other top Zerg players have all commented on the imbalance of the match-up at their level.
I doubt there's real game imbalance.
To understand my reasoning, first you have to understand the difference between imbalance at the top level and "high" level, that popularity isn't the same as strength, and what imbalance even means.
When Dimaga says that he might have to switch from Z to T to produce results for his sponsor, what he's saying doesn't apply to players who are mid Diamond, or even top 10 level Diamond. Until you are at a truly professional level of gameplay, the imbalances don't even matter, because you're making mistakes that are losing you the game, before any sort of imbalance can even come into play. The top level players are commenting on facets of metagame that don't likely apply to all levels of gameplay.
People also typically confuse how many people play something with how strong something is. If 40,000 people are all doing the same strategies, it might as well be a single person doing those strategies, because all that matters is how flawlessly they are executed. Why do you need 40,000 players to be Zerg if they are all doing the same thing?
If Idra is the only Zerg player in the world, yet is still successful with his race in a tournament setting, then the race is probably fine. The same goes for if Idra is the only zerg in the top 200, etc. If he can do it, you can do it too. Not only that, but you can do it better than him too.
Next, let's talk about what imbalance even means. True imbalance would mean that, no matter what strategy the Zerg player uses, if he plays perfectly against a Terran who is also playing perfectly, he will lose.
That is plausible, however extremely unlikely. The problem with this is that the game is very, very young. Pretend the upcoming expansions are never going to be released. What do you think players will be doing in 5 or even 10 years? Do you really think they will be using the same old strategies from today, with no new developments or improvements?
It's highly likely that a Zerg build from 5 years in the future will be able to defeat any Terran build of today. Because of this fact, the imbalance isn't the game, it's the player. Or more specifically, the strategies he's using.
All through-out the history of BW, one race would dominate another. Did that make one race superior? No. It was all metagame strategy. Currently, Terrans are dominating BW in the pro scene. Does this mean that Terran is OP? No, it means that Toss and Zerg need to think of viable counter strategies, and they doubtlessly will eventually... assuming SC2 doesn't kill BW competition, at least.
When I play and lose, it's so obvious that I've made a mistake, either in overall strategy, in some specific tactic, or in the overall smoothness of my build, that imbalance doesn't even cross my mind.
My point is, though, that balance shouldn't even really be a consideration of players right now... It was during beta because some thing were completely ridiculous. ATM, however, everything is very close to being balanced.
I haven't yet seen a player lose a tournament match and not known what mistake he made that lost him the game. If you're losing because of mistakes, then you aren't losing because of imbalance.
So what I'd say is, instead of saying there's game imbalance, strain your brain to find a strategy that can win. Think outside the box. Even if your idea seems silly, find a way to make it work, and maybe you'll be the one to end the "ZvT imbalance". Good luck and have fun :3.