Nintendo has shown the ability to patch gamesave related bugs by patching the System Menu to erase saved games containing malformatted string data, which has been done thrice - once to kill the Twilight Hack, once to fix the check that didn't work, and once again to prove third time's the charm.
Bugs in the System Menu itself can be fixed by shipping a new update with corrected data handling code. In the case of Bannerbomb, this also took two tries - once to show why testing all suspect code paths are a good idea, and once to show that Nintendo takes too long to fix bugs.
The two currently working exploits are Indiana Pwns, which affects gamesave data, and Smash Stack, which attacks Super Smash Bros. Brawl's ability to load SD card data in-game. Nintendo has not yet attempted to fix Smash Stack, most likely because the Wii has no way to patch games.
Put in your Infobox homebrew under type "exploit".