I use Renoise as rewire secondary (slave) in Reaper, and use Reaper to send recorded midi events to it. This workflow is really great for me for lots of reasons, basically I prefer the DAW-like interface to the tracker for entering notes, but love the flexibility of Renoise sampling capabilities.
What I sometimes do though is record a live audio track into Reaper to go along with the midi events that are being synthesized by Renoise. Everything works, but I can’t mix the live audio track in Renoise, because the ReWire Input only works when Renoise is the ReWire primary (master). Instead, I have to use Reaper plugins/etc. to mix the live audio track, while everything else I mix in Renoise.
If this routing plugin could work with Renoise as the ReWire secondary, then I could send audio to it from any live tracks I record in Reaper. This (I think) would let me do all my mixing and track effects in Renoise, which would really help keep things cohesive.
Hopefully this makes sense.
Side note to the devs: absolutely love Renoise! In my teens and 20s I did a ton of music in ST3 and IT but the tracker note entry interface for me just never really gelled as a way to make music. Sample based music OTOH-- that part I always loved and found so inspiring. Reanoise has so many wonderful, creative features for working with samples and is so incredibly rock solid as a piece of software art. So for me, being able to use a DAW to record midi notes while having a tracker-like sound engine to play with has been so much fun. Adding live recording on top of that is a really fun prospect.