Monsters should deal more damage, or have more HP, or just be more of them...
All the re-tweaking and testing, and further tweaking and testing of the already existing content (also act 2-3-...) for 3, 5, 6 party members would be a lot of time. And if they implement it, then people would start complaining about how they implemented it, and why it should be done differently...
Not sure it is for us to determine how labour intensive it would or wouldn't be in terms of implementation and balance, I am pretty sure Larian themselves can determine that.
If enough people clamour for 5-6 party members, then there is appetite there for the change to be a valid one. Now Larian might feel the game is better with 4 PC's and they'll allow 5-6 purely as NPC types (limited interaction / story), because it is easier to manage the game if people like Halsin can join a 4 person party rather than joining a 6 person party, where either someone has to temporarily leave, OR suddenly the party grows to 7+. For me that seems to be the crux, in that story elements are designed for people to join you in specific quests / missions and perhaps at larger party sizes it get's too hard to balance or the system starts having a GPU meltdown, I don't know. Either way Larian will I am sure. There are ways round that, such as you choosing to meet the NPC at a set location vs integrating them into the party for example, depends how much exposition is needed.
The only thing that bugs me is that Larian have stayed pretty quiet on this topic despite it, for all intents and purposes, being quite a big topic at least on this forum. Many here, myself included would like to see larger party sizes being a legit option (i.e. not just through mods) and are keen to at least understand the reasoning behind the decision should it stay as is, or better convince Larian otherwise.
Would that mean something else wouldn't get implemented? Maybe, but other than Day/Night or RTwP, what other large topics are there? Until Larian starts giving us a poll saying you can have Day/Night OR Dragonborn, you can have 5-6 Party size OR 10 extra quests, blah, discussions on how much work for Larian it is or isn't, is an irrelevant discussion. More pertinent is only how do we feel about thow the game plays vs how we want it to play and our reasons for and against. Leave the rest to Larian.
