Hi,
no plans to add such a feature no, we really just try to focus on the available hardware settings when it comes to "sprite attributes" and the animation system really just focuses on image frame sequencing rather than actual sprite movements.
I'm not saying it's a bad idea but it seems to me that such a system could be implemented quite easily in your particular game's sprite engine without needing SpritePad to provide special support for it.
Where would we even be able to show moving sprites in SpritePad's current interface?
It would require great changes to the interface and bring absolutely no benefit for most users.