I took a look at third party tools like Poser (animation tool) and Tatoo (paint your skin directly on the 3D AV!) and there is something that is sorely missing in SL: an export tool.
Animations in poser are very dependent of the AV's size and limbs length ; so designing an animation that looks good on your AV is often hit and miss as it doesn't look the same on poser and IW.
Skin and clothing is another problem. Tools like tatoo import the SL Avatar model, let you paint on it and save textures which are ready to import in SL. It's handy but the model is a standard SL avatar, if you customized your shape the texture will obviously not look the same on your AV IW.
I think it would be great to have an export tool. Even if only for your AV's shape.
It would be great if it included attachments in it too, so that you can texture your robot/furry/whatever AV offworld in a program designed to do it.
I don't think it would be a problem on the IP right point of view since there are no import tools for 3D models, and will likely never be any. But even if it was restricted to objects you are the creator of or have all perms on, it'd still be very useful ...