I had to make my first post because I don't think I've seen anyone comment on the 'shove' action. It's a simple mechanic that seems to be pretty darn useful.
In 3e I noticed players never using the special attacks (bull rush, overrun, grapple, trip, disarm, etc) unless it was the focus of their entire build, just because they were so damn complex. No one wanted to be the guy who brought the combat to a halt thumbing through the PHB to figure out if he could knock the orc over instead of just whacking it.
Just reading the Basic rules for 5th, I'm excited to see more pushes and shoves being mixed into combat without much fuss.
Welcome to the boards!
Good call -- the unification of mechanics with grappling too is elegant:
Attacker's (Athletics) vs. defender's (either athletics or acrobatics) puts the onus on the attacker, but allows for interesting effects in combat.