1) Impact XT could have a much bigger library of sounds. Then the question of using third party stuff would come down making production lot easier.
2) Adding Automation feature/gain envelope within Impact XT could be amazing.
3) An inbuilt mixer inside Impact would be cleaner instead of individually creating tracks in mixer window routed to output numbers. In case I have 20 samples loaded into one preset file, assigning these sound outputs one by one to the corresponding output number nearly 20 times is tedious. Furthermore, I don't really prefer any plugin to create extra tracks in the mixer window as it would get crammed with fader tracks. Just the inbuilt mixer feeding into one master fader panel (just like every other plugin) would suffice.
4) I don't know why but the order of pads w.r.t MIDI keyboard in Impact XT are bottom to top (C1 to B1). Slightly counterintuitive and peculiar as every other sampler has top to bottom order of pads.
5) Better Highlighting options- When the pad is struck, the color should be brighter and fill more.
6) Auditioning pads- An option to compare pads while browsing through presets could be implemented.
7) In the event of importing a midi sound existing in a track, S1 should automatically export the sound by transforming the audio track at that region and load it into Impact XT via Drag and Drop. Ordinarily, one has to select the region, bounce the file onto a new audio track, import into Impact XT and then delete the audio track. One neat feature that would be convenient.
8) Fade in/out controls.
9) With the addition of Inbuilt mixer, Send FX could be added with controls of wet effects to which would decongest plugins in tracks.