Honestly like I mentioned above just create a Delay engine . like they did for chorus/ flanger
with your options for mutlitap, diffusion , ducking , reverse , then let users create their own , its easier than going lets do a BossDD2 and tera echo and strymon
Port the spring verb from Morgan as most people seem to like that , add a few amp models , pedal models and call it a day
there 3.1 update September /October
and better wah. with more control of the sweep , or Wah engine
also I cannot recall but does QC have the room mics of the plugins in the cab block?