while shoving is extremely strong right now, its comes down more to the IA than the mechanics:
If enemy start shoving you as well, such as the goblin priestess, battle become extremely hard . This may be enabled on harder difficulty setting or later in the adventure. Maybe they wanted an easier start with ''dumb'' enemies , goblin being traditionally low int, and would make smarter enemy use the shove mechanics more liberally.
Second, the enemy position badly , making shove easy to land. If enemy moved smarted the mechanics wouldn't be nearly so overpowered. This is definitly a decision of game design to make the game not too hard and enable use of the mechanics (its fun to drop goblin off a cliff).
Overall, I think the mechanics is nice, and will be adjusted later in the adventure / in other difficulty mode.
However, if its stay as it is, its definitly too strong imo, its an instantkill button in most cases.
There's literally nothing from Larian that indicates they have any inclination of changing the mechanics from their current state, quite the opposite given the statements they made in the panel from hell 2.
None of us should hold our breath for a final release of BG3 that isn't inundated with DOS mechanics, and Larian's game-breaking homebrew rule changes.