StarCraft Broodwar is about as balanced as Chess.
http://en.wikipedia.org/wiki/First-move_advantage_in_chess
"Statistics compiled since 1851 support this view, showing that White consistently wins slightly more often than Black, usually scoring between 52 and 56 percent."
Non-mirror match-ups in Professional Broodwar, lifetime, are between 52-54%, irrc. During some seasons, due to play-style shifts and map balance, a particular match-up is usually no worse than 58%.
Hopefully Starcraft 2 can keep the tradition alive.
I totally agree.
Part of the "problem" is that balance can't really be static unless everything has been explored.
In SC that's taken a long time, and even when it's balanced as you say, maps can make a big difference.
Something like SC/SC2 has so many things which can alter balance that the best anyone can hope for is decent balance.
Even (for some reason) the unbalanced maps which get used in pro-tournies keep getting used, so they can be basically deliberately unbalanced. Often in the team league teams send out specific races to avoid playing a weak race (weak because the map favours other races).
SC is kind of balanced, but only when you play balanced maps, and that's what's most important. Keeping a game fresh requires fresh stuff to play, which (IMO) means fresh maps to develop new strategies on, and when the maps play a big part in balance, there's only so much Blizzard can do to make a balanced game as a whole.
Even now, in 2010, many years after Broodwar, there is some evolution of some matches, even mirror matchups. You can't balance forever when there are creative people doing creative things both with their play, and mappers doing creative things with maps. They best you can hope for is "balanced enough", which is what BW has pretty much achieved.
SC2 might be there, it might not, but Blizzard shouldn't and can't do everything, because it's also up to custom mappers to make the game fresh and up to the players to adapt and develop unit uses and playstyles.
I mean, if Blizz see something as "unbalanced" in beta testing, is it really unbalanced, or has it just not yet been countered yet? An early rush is unbalanced against someone fast expanding in SCBW, so it's a very delicate process.