Constant balancing would be terrible. Games have to be left to allow a metagame to develop. If developers were constantly messing around with characters because they didn't like how the character was played by the players the players will feel like they are being punished for playing and will stop playing. There should definitely be a final product with no further edits.
(look at what happened to wizzy... and brawl+)
Well, using sc2 as an example, constantly messing with the game brought a stable meta game, they changed a lot of things, but they were small. During the hots beta they updated like every week to work out obvious kinks, imbalances. But after a while they slowed to allow meta game strategies to develop, these last updates are to merely help shape the meta game that has already been established, not overhaul it completely. As of now I see project m in the beginning stages of sc2, a developing meta game with the assistance of the game developers. Once the "Final Product" is released if they updated it at all it would be to help shape the meta game that has already been established.
If they were to release a final version with no updates they would have to get everything just right, and if there was an exploit discovered, players would abuse the hell out of it, or it could end up like melee with like 10 viable characters.
So small updates after final release? Thumbs up from me
StarCraft 2 is awesome