I just think enemies need to be Shoving us just as much, that would make the combat even more tactical as we'd have to really consider whether or not we were in a vulnerable position to be Shoved.
Also, RE: Shield Master, they should just give advantage to Shoves if you have the feat and a shield.
I was mighty surprised when one of the Zhentarim pushed Wyll(?) into the dark abyss. Sure doesn't happen enough :P
As for topic. Sounds like a nice way to go about a shove rebalancing.
