Every major problem with BG3 can be traced to the limitations of Larian's home-brew engine: cannot pause the game during real-time exploration; no day-night cycle; toilet-chain party movement; inability to do reactions properly; etc. Everything is because of the Larian engine's limitations.
Is it, though? What makes you think that if Larian were working with other engine, they wouldn't still design the game with multiplayer first in mind. Game with far smaller budget has stuff you mentioned - seems more like a design decision then an engine limitation.
But Larian's choice of MP first was not there in my list of BG3 game design limitations due to their engine (the very part of my post that you quote in you post).
It seems like Wormerine's point is that Larian's desire for MP first that is the
cause of these problems you list, not engine limitations.
In an
interview, Larian's reason for no day-night cycles was: "We're a multiplayer game and day-night cycles in multiplayer becomes incredibly complicated." I.e., since time can pass differently for players in TB vs real-time exploration, creating perfectly realistic time-dependent NPC schedules is too difficult.
In fact, I'd attribute most of your list to design decisions, not engine limitations.
- Toilet chain is a combination of Larian's historical preferences ("don't fix what ain't broken") and to make the experience "better" for console players.
- Automatic reactions are to make combat quicker & smoother. Related to the Engine: BG3 already has pop-ups---tool tips and quest rewards--I could easily see these pop-ups being extended to reactions during combat.
- I don't have direct evidence that Larian's engine can handle a game-wide pause, but I similarly don't have evidence that it can't. It's likely that Larian hasn't implemented this for similar reasons as for day-night cycles: "it'd introduce problems for time passage in multiplayer." (ignoring the solution of one person pausing causing a full pause for everyone)
(Everything above is being argued from Larian's POV: e.g., their ideas of what is better. Almost all of which I disagree with.)
