Well, in a DnD session you wouldn't be able to cross a line that your opponent doesn't want you to cross without consequences.
And just read the exemple I gave and you quoted... This wouldn't happen in a DnD session.
And in a DnD session you wouldn't be able to cross the entire map while someone is stuck in dialogs (or in combats).
You can make your arguments but please, stop thinking your point of view is the only valuable one.
I was waiting for you here because I knew you'll bring interresting arguments for MP... But your last sentence is just stupid and out of topic.
This system is far from being perfect. This thread was made to discuss about it and eventually think about solutions.
I think the most obvious solution would be to make combat triggers for each potential enemy IF engaged in a dialogue as opposed to standing still. But then you end up with " inconsistent" encounters where you don't know how far you can go as the 2nd player before it starts combat.
Alternatively you could simply include the player trying to move around freely FORCED in the dialogue the same way the 1st player was if he's not sneaking.
You could have a discussion with the goblins ambushing you, the other player tries to move around without sneaking , he gets to close ( maybe based on existing LOS features?) and simply gets a short dialogue " You there, you think I didn't see you? Stop right there or die!. Staff like that.
Not necessarily a mechanic preventing you from moving ( as @maximus mentioned entering turn based mode where effectively...you have to wait for the end of the enemy turn. That turn being his dialogue).
Rather a clear warning " One step more and we kill all of you. "
