ok, as I always have enough time to procrastinate on the important stuff in life, some ideas for the tools forum 
I once tested, reviewed a slicer program, which main selling pitch was the ability to do multi-track slicing and quantizing (zero-x beatquantizer), but it also had some nice little tools, which might be interesting to emulate.
Re-arrange slices:
I think the picture is self-explanatory,
…but say you slice a beat, then opening this feature displays the waveform with corresponding slice-marker numbers (1 to N). You can select slices through clicking the numbers in the drop down list or through mouse clicking slices in the waveform, and drag/move them around.
What I like in this tool is the option to quickly randomize the slices and save/open so called slicer-arrangements (which are nothing but order lists that can be used to order other loops).
Next up…
Slice-Processor:
This tool doesn’t re-arrange the slices (although slice arrangements can be imported), but can be used to apply different dsp settings on all or individual slices. In the case of beatquantizer, the effects are filters and pitching parameters, maybe in Renoise this could be linked to the available track dsp’s in a track (have the user select which parameters he/she wants to have applied?), in combination with the ‘fx’ button in the sample editor? 
Again the randomization in this tool is what I find attractive, a quick and powerful way to manipulate sounds. Beatquantizer runs through the slices and applies different filters, resonance and frequency settings, I can only imagine selecting and running various dsp/vst settings on slices in Renoise and have the results rendered into the sample.
In the same processing vain, though slightly different is the:
Pattern Controlled Processor:
Here the numbers displayed inside the tool, don’t represent the slices as in the previous screenshots, but stand for the amount an effect is applied on that slice. Different number orderings can be saved, loaded or (randomly) generated.
Maybe some of the above functionalities can be used for inspiration in a new tool for manipulating slices?