For live performance with Impact, it would be nice if the quantize and loop feature would react exactly the same way on the start and end of the quantize selection. For live performance, it would finish the loop at the end of the bar for example so you could trigger its end ahead of time. A little bit like Seq24 used to do for midi clips where you could trigger off a clip that would then finish and then stop.
Also, if you could assign patterns to Impact with a midi out instrument and channel, you could trigger midi clip. Again, would be a very nice way to do live performance within Studio One.