How do I uninstall StarCraft II on OS X?
Solution 1:
The standard procedure is just moving the Starcraft II folder from Applications to the Trash. Your save-games,replays etc. are stored in ~/Library/Application Support/Blizzard/Starcraft II/
. If you keep that folder, your save-games should still be there after a re-install. I haven't tested this though, so I suggest you make a backup copy of that folder before you perform a fresh install.
Solution 2:
If you have StarCraft II, you probably installed it from Battle.net in the first place. If you look at the game's tab, there is a settings gear icon with a drop-down menu which has an uninstall option. Battle.net tracks your progress and saves in the games that are linked to it, so reinstalling later will recover this data. No sweat!