I keep seeing bufferbloat in userspace proxies and tunnels, and think that the world would benefit greatly from aqm library for applications to use in order to keep latency under control.  Especially if work like encryption is being done and the results thrown away due to massive tail drops and the like (or "real-time" video streams that need to throw away a bunch of received packets in order to catch back up the proper e2e latency.

(no I'm not volunteering at this time, nor am I obliquely asking anyone else to...)