I like the solution Heroes of Newerth provided for heroes like Bubbles (Puck in DotA).
Using his first skill (Shell Surf) will override it with a subability which does the second part of the ability (jumping to that location). So in HoN only one button is needed to do both parts of the spell.
In DotA however Valve copied WC3s limited design and you need to use another button to do the second part.
Is there a way to make skills with subabilities only use one button like HoN did?