You should probably compare the whole DnD spell list to compare with DoS. You know that Larian hasn't implemented all the spells yet right ?
For the end no : it's not a matter of AI tuning, it's a matter of balance.
The ennemy won't shove you often EVEN if you're close to a cliff and they won't backstab you intentionaly except in very rare occasion.
You can use the occasion to say I'm wrong but after more than 300H playing I never saw the AI using backstab whatever it's a rogue or not and pushing my characters efficiently (like players).
And you know what ? the game would be even more frustrating if the ennemy was using this.
No one should be able to use such OP mechanics because this unbalance everything. This is definitely a matter of combat overhaul and balance.
I linked you BG2's spell list. Go read. Yes the enemy
will shove you, I've had it happen on several occasions. Pushed off the high ground at the Goblin checkpoint, pushed off the beam in the Bugbear boss room, got pushed off the ledge in the Drow boss room, and seen the AI push a troll off into the Spider cave.