Two suggestions here…
It would rock if renoise would recall the position for of the marker (or selection) in the sample editor for each sample, instead of resetting to the beginning. Often I’m flipping between samples which are to be chopped in various locations, and it always resets. 
a little xml with the last position/selection, for each sample maybe? 
It would also be incredibly useful if there was also an option to playback using the keyboard FROM the current position (or selection). Kinda how [enter] works now… It plays back from the current position thru the selection. This would let us switch up the octaves and what not.
As a whole it would make it a lot easier to test ideas before destructively chopping up a sample. 