I'd actually prefer if they don't put too many 'stretch goals'. They are really not part of the game (Mac/Linux support, even housing, etc). An RPG is a complex thing, as they well know, adding one extra node to the graph means connecting that node to all the other nodes in the game, it's not a linear progression of work, it's more exponential.
I'd say, stay as it is, and make the game as originally planned. As we all know there will be delays, and the extra money they get should go to cover those inevitable delays.
Once the first game is done, the engine is done, the assets are there, then the sequel can introduce extra races, classes, etc. Building on what's done.