EA is way too late in the development cycle for this. Z.
No, its' not. We aren't talking about a massive redesign, we are talking about UI tweaking and eventually rebalancing encounters, which is something that will go on for a while regardless of any change to the party size. If modders could find a (fairly half-assed) way to introduce six party members in DOS, Larian with full time paid devs and a gargantual budget compared to their previous productions COULD absolutely achieve this type of change with relative ease, IF they want to commit to it.
you are totally right, some modders did enlarge the size of party in DOS2, if i remember correctly, the only things that prevented Larian from making a 6 man party was the time and funds, now they got the funds (They cannot say the EA wasn't a success), i hope there is still time for it, so we need our voices to be heard by Larian.