If players can ambush properly in MP without any form of pause that's cool I guess, but if it means the only way to ambush properly is in Co-Op that's pretty lame.
I am assuming in multiplayer that the party has proper communication and they can all move into position and attack at the same time. If they change the current system to what some people are wanting, then it effectively removes the most logical and useful stealth tactic from single player. I understand their reasons for wanting the change, but it will make things extremely aggravating and miserable for me if 3 of my 4 stealthy characters are always assumed to be revealing their positions like idiots.
[ It can be handled, if one feels it is needed - Solasta has a surprise round - enemies who were ambushed don’t get to act on their first round (works well, there, might be too much for BG3 as characters can move rather far in one turn). There could also be a free half-turn for ambushes - like in Pathfinder games. Possibilities are many.
It is definitely needed. Never played Solasta, but if this system would give the entire party time to act in the surprise round, then this sounds like a great idea. This could even be tied into a readied/queued action system if people are bothered by having a full round to have both movement and attacking.