Its been a while since I came here, indeed a while since Ive been skinning Xion too!
But while working on my latest skin, I came up with some ideas:
For animation, I thought it would be cool to add a ping-pong option to the direction command, ie an animation that goes up-down-up-down the list. Im not sure it would be used heavily, but it would definitely save layers for people who do that sort of thing.
Also, I though it would be cool if there was a command to change the clickable area of buttons in a similar way to the snaprectangle command. For example when Im using shadows on buttons they sometimes cross over and theres a point where more than one button is highlighted.
Im sure I had other minor things that I cant remember, but anywhoo...
Share your comments and add to these if theres things Im missing

Thanks