I think encouraging players to utilize verticality and push/pull people off ledges is definitely part of D&D. It's not just a DOS2 invention. There's more to D&D than just attacking with your weapon. The game rewards creativity, especially if you have a DM that is any good.
That said, the rules should more accurately represent D&D 5e. Not being a bonus action is probably a good start. That's what made pushing attack so good for Fighters. You could hit a target AND push them at the same time. Now you just get an extra push.
You're not wrong, but missing the point.
Yes push/pull is a D&D mechanic. A LIMITED mechanic. Push moves a opponent 5 feet in 5e, not blasting him/her into the void like seems to happen in this early access release. Similarly, pull mechanics like the Warlock invocation pull at most 10 feet, and you have to hit with your attack. True Soul Gut's gloves work every time literally drags your character in a straight line, and has a ludicrous range.
Furthermore, D&D adventures at lvl 3 generally do not involve 100 foot drops to be thrown down. As someone who has been involved with 5e since it's inception I can attest to that. Push/Pull is a minor mechanic in 5e, and only very rarely does it ever generate instant death. This is the developers unable to resist DOS2 style shenanigans, not a D&D thing.
