would be nice to have another delay for filtered delays! delays always sound better with some cutoff 
can’t you set up a chain for this (for example: Use a send, add a delay device to it and mute source, add a filter and automate cut-off )or simply get a good vst? 
yeah i guess i could use a vst but you could say that about every over dsp with renoise its just nice have something right there rather then using up time 
A good setup would be:
Delay > Signal Follower (High sensitivity +/- 75%) > Filter 3 (Signal Follow Cutoff).
Bam!