I don't know if this is feasible, but I think it would be helpful to be able bring up the intellisense menu by clicking on an attribute. Like clicking on "X" after "sprite.X". That would make it really quick and easy to select another attribute, or another variable.
I realize that it might conflict with selecting text though. My best idea is to put a colored round button underneath it with a downward facing triangle at the right, so the user could both click on the triangle to bring up the menu, and they could still click on the word to edit it via typing.
Food for thought.