what would be enormously useful is a return meta device in addition to the send device. in fruity loops i would set up complex fx chains that were very helpful using a VST called senderella. the idea with this plugin is that you make several instances of it in any number of fx tracks and you can set each of these instances to either “send” or “return” and you can set the channel that they send or recieve on.
this allows you to say, have a drum track where you have two sends, each going to two other tracks. one of these tracks has highpass and a bitcrusher, while the other has lowpass and distortion. they both are sent back to the original track where they are compressed. this allows you to bitcrush the high frequencies, distort the low frequencies, leave the midrange untouched and combine them all again. this is possible with the send channels, but requires making 3 of them, and there’s wierd restrictions on the order they can be in.
there are also many other things that are possible with this. you can make a delay that becomes progressively more chorussed with each repition for example.
unfortunately, senderella doesn’t work in renoise for some reason. this is why i would like to see “return” integrated as a meta device (or as an option on the “send” device)