Loop browser/Instrument browser
It's probably on here somewhere already, but this is one of my pet hates with Reason.
Apple Garageband/Logic do this so much better. You can asily view collections (e.g. Jam packs), then view instruments, then click to instantly load.
Preview then drag and drop loops to the sequencer! Simple and would speed loops up.
There is no need to view the file extension of any intrument/patch- not very user friendly.
You could have a floating window similar to the Spectrum Analyser that is a browser for intruments/loops, you can preview in the window then drag/drop or click to add to track.
Just thinking out loud.