Whenever I launch IWD2 it force disables Windows aero, this wouldn't be an issue except that the basic theme causes very noticeable screen tearing when I scroll the camera. I Could MAYBE tolerate it but it's pretty annoying so I'm wondering if there's any way to get the game to stop closing aero on launch.

Failing that Is there any way to force vsync? There doesn't seem to be an option for it in game.

It does not disable Aero by default. If your game is disabling themes, then you have your shortcut set to do so in the 'Compatibility' tab. Check it and change it. It does NOT need any compatibility settings whatsoever.