"How is that any different than automating the channel fader? A gain plug, whether it's before or after the reverb on a channel will adjust the volume of the entire channel."
.
.
Hi iSchwartz,
sure, there is a difference!
If you pull down the fader of the gainer-plug-in (which has to be placed before the reverb) fastly downwards, you will still here the reverberation from the reverb-plug-in (depending on the reverb time of the rev-plug). Its like a natural fade away..
If you fastly pull down the fader of the channelstrip, the reverberation will be cut immediately which can sound unnatural (unless you use a send for the reverb, but thats not what the OP wants).
And pulling down the direct level of the reverb has a totally different effect. You will hear only the reverberation which remains as long as the fader of the channel strip is open.
Eddie