We do need the ability to switch each channel to pre/post. But your second request we already have, you can use USB to run external plugins, just pick a mix, send the channels you want to the reverb mix, then send the mix over USB to your host of choice and return it to any free input channel, then send that channel signal where ever you need the reverb.
Another pro tip is that all the the 32 channels already do have external plugins inserts, they just aren't called that but you can route every channel to something like waves live performer and return it directly to the same channel through usb but processed with a any vst plugins of choice.
