Vertical Sync drops FPS

[Your Computer]

DirectX support was probably for Xbox support, but IIRC they're not bothering with console support yet. There won't necessarily be less problems (though, this is not to say that there will be problems). Most technical support issues here deal with hardware and driver limitations, which isn't an issue of the game itself and can also be found for DirectX games. Duplicating your work for the PC market when there's no real return for it wouldn't make sense.