I think that a content creating contest for wining a redux license could be a great way for building a good library.
This could also be a great way to stimulate sells of redux for non renoise user once its ready !
I must agree. BUT! You dont have the new filters so… 
MuLab does something simillar (you have to create a nice demo song).
You can do a lot even without the new filters, you just need to free your mind (and your oscillators too probably :p). But I think only word of mouth will help renoise and quite a few effects will be changed altogether, wouldn’t be too nice if the demos have a bunch of hidden deprecated devices 