Apologies if this has already been addressed.
I noticed that Shove is set as a bonus action rather than an action. This pretty much removes half the reason to take Shield Master as a feat. In the same vain I notice that Shield bash has been removed from the Shield Master feat. Seems odd given you have the mechanic already in place, As far as game play with Shove thus far, it seems a bit OP as a bonus action. I am pushing people off cliffs and buildings with abandon, with all players. In a lot of situations its my default bonus action over others especially if I marry it with those things that grant saving throw bonuses.
Why not push Shove to an action per the rules, grant it as a bonus action for those that have the Shield Master feat? It grants more utility to Shield Master, makes it less inviting to other character classes that would normally be less inclined to use up their action for the Shove feature and thus balance is achieved.
Just a shove for thought.
