5e has a mechanic called "surprise", which happens when your rogue rolls stealth and beats the enemy's passive perception score.
A surprised target can not move or take any actions during the first round of combat, and the Assassin has a skill that grants him advantage ( roll twice for attack) and an automatic crítical hit if he succeeds.
I really hope they implement this mechanic into BG3, and I'm curious to see how this could be implemented without turn based combat.
Most of these should be simple enough to implement in RTWP, even if not in an exact same manner. The perception check against stealth is there in NWN and Dragon Age Origins. The auto-crit effect is also simple.
The advantage thing is more or less like the +4 attack roll bonus when attacking out of stealth in BG1-2. They may not be exactly the same technically, but the idea is the same: you are more likely to land the attack. From this angle, the concept of "attack roll bonus" makes more sense to me than the "rolling one more time" thing.
As for the not being able to move or take actions for one round, the only thing close to that that I know of is the delay timer in Pathfinder: Kingmaker. When combat starts everyone gets a countdown timer based on their initiative roll. You can still move, but you can't do anything else before this timer runs out. When I was playing that game, sometimes I could go make myself a coffee then came back and the timers on some of my party members would still be running.
