I agree Starcraft could use another balance patch.
Off the top of my head:
Ghost, Queen, and Scout, have no place in competitive play beyond humiliation units. They could all use modifications in order to become a serious part of the game.
Battlecruisers and Valkeryies could use slight modifications as they are so far specialized that they appear in less than 5% of competitive games. Dark archons are also somewhat like this but not too such an extent.
Terran Bionic units are effective against Zerg and completely useless in any other match up. Lately they have been being used less even against Zerg in favor of Mech. I'm not sure if anything at all could be changed here to increase infantry viability in competitive play.
With the "Why fix what isn't broken" attitude the game will always remain "almost perfect" instead of "perfect". Why not try to make it more perfect? If these three points were addressed I think I would consider Starcraft even closer to that ideal of "perfection".