It would be a nice feature to have a remove unused samples function in reason, especially for songs which have to load large kits with alot of mapped velocity layers like drums/piano's/etc (the user can just reload the kit again if they want all the velocity layers). It's also great for those lazy people who seem to add alot of things in nn19/nnxt/device/instrument whatever but aren't particularly using it in the song/sequencer, perhaps make a popup dialogue to choose to load all samples, or only relevant samples that are used in the song. This could well save on cpu/ram for those with weaker computer specs.
Another feature I think that would be a big help is an optimize feature, something similar to the 'Cleanup' function in an app like modplug, where unused patterns or anything irrelevant is removed or not loaded/displayed and the song is 'cleaned up'. Maybe to have it also optimize wiring between devices, so instead of having something duped several times, reason intelligently figures out that it can just do it with less devices [maybe even spidering things together], thus further lowering cpu usage. You could have a menu for 'Remove/load unused samples' and 'Load/Unload optimized' so that the song can be loaded as it was made originally or optimized. I can see the remove/load unused samples thing happening before the optimize feature though, as it probably won't require as much code. Oh yeah I forgot to add one more thing, it's about the redrum. I'm sure I'm not the only one who's come across this. I want to be able to copy the steps of a pattern, i.e. whatever is on 1-16, to 17-32 etc because you can only copy the whole pattern. It's a little tedious trying to copy whole segments of certain steps in the redrum let's say I have 64 steps and I wanted 1-16 to be copied to 49-64 instead of having to manually fill it in [of course copy pattern won't do this, because we specifically need steps 1-16 to be copied to 49-64 in the actual pattern]. I hope my explanations have been somewhat clear enough to understand. but I do hope you take these suggestions into consideration