1) In the 1st versions of TE4, the drive volley was triggering very often and many people complained about it, so I said it'll make it selectable ; actually, now that I implemented the strike prediction and that it's working correctly, there's almost no drive volley anymore, and no one complain... So maybe if I manage to add the context-sensitive action button, I'll make it trigger the drive volley when we run to the net, but it's actually not sure right now, as it's not much needed.
2) clay movement, sliding (so it'd trigger more often), side spin (ditto), seldom very fast serve, faster 2nd serve ; and probably others depending on the need for the gameplay tuning
3) I'm done with new animation features (more or less), but I'm still fixing issues in the dynamic animation system (although the last few fixes may have been removed the last big issues ; now it may only have a few small ones left to fix).
After the v1.0 (and the release on consoles), I'll try to improve the running animation like shown in the mini-blog : viewtopic.php?p=281103#p281103