One thing I DON'T want to see is half-a-game at the base funding goal. I've seen too many Kickstarter projects promise features at higher funding levels that should be in the game to start with, or at least should not be explicitly tied to a dollar figure (extra levels, multiplayer etc), to encourage people to keep donating just so the game ends up decent.
I understand that more money leads to more development time and a better game, but to explicitly say "we'll put this stuff in precisely if you give us X dollars" just seems to me like an excuse to plead for more funding. More funding is great, but the tactics commonly used are deceiving and depressing. The developers should put in their best possible effort regardless of the funding. They can't pretend to know that X levels cost Y dollars.
Perhaps you can do something a little innovative, if/when the base goal is reached, start giving a bi-weekly update on what the current extra funding will allow for, and what additional (future) funding could be used for.
The stretch goals I like best are "fun" stretch goals, not a shopping list of features that should be in the base tier.