I would like to see an option added to the GUI for disabling the mouse cursor that ScummVM adds to older AGI games (King's Quest I, II and III, for example) that did not have a cursor in their original versions. It's a nuisance if you have a cursor and don't want to use it, and it's a distraction if you're playing the game for recording purposes or taking screenshots.
Probably an obvious suggestion, but program SCI0 games to hide the mouse cursor if it isn't moved for a couple of seconds. Then automatically re-show it again if the mouse is moved later on.