I do not think it should be a default -- texture memory can be a precious thing. Besides, things can look bad if they were all textures. Being able to set a default for new animations, though, is a good idea.
I would, however, support trying to make these trigger that, because they do with plain CSS: 1) "transform: 'translate3d(0, 0, 0)'" -- without killing Greensock specific sub-transforms (or vice-versa) in the process.
2) "{x: 0, y: 0, z: 0}" -- one of these needs a small value to make the 3D texturing work...