Why though? I know for sure you played the dragon age games which had 4 party members. Why disqualify this specific game solely based on this?
@Tuco's already said what I would say, which is that in a classless (or pseudo-class) system like DA and D:OS a party of 4 is fine. In a system that is the classic standard for being all about classes (and yes this is how I see D&D even with all the 5e changes; D&D is ALL about classes as far as I am concerned), and where that system provides so many classes (and then also subclasses, archetypes, and multiclassing), anything less than 6 for my party size is aggravatingly limiting. As I have been posting on the P:WotR forum, one of the things I love the most about party-based RPGs is assigning specific party roles to my party members (and again, please don't bother telling me that in 5e this is not needed because I don't care). I need in my party: a tank, a melee damage dealer, a ranged damage dealer, a healer, and a crowd-controller and buffer. The sixth spot, then, is for that eclectic companion who may not necessarily satisfy a particular party role but who brings something unique or special to the party. So, 6.
after playing the game yesterday I actually agree with that. I don't think it is deal-breaking not to have it, but I think what you are saying here is the ideal way to play.
Originally Posted by Alyssa_Fox
Being limited in content by who you can group with is akin to being limited in content by making choices in quests that exclude you from other quests. Like doing Thieve's Guild path to get to the Asylum in BG2 excludes you from doing Vampire path to get to said Asylum. There's nothing wrong with that. Wanting more while ignoring deliberating consequences for other players is just selfish and greedy.
I talked about it at length before, but as far as I see it, there are two ways to increase replay value, aside from the obvious of "make a good memorable experience and people will replay it even if it's completely linear". one way is to branch the story - you write two different scenarios based on the player choice. this is the example you gave. the other way is to create something (be it by story or gameplay) that forces the player to not have access to content. A good example is what Larian did with companions in DOS2. they just randomly killed off the ones you didn't choose. has nothing to do with the characters themselves, just arbitrarily killing the characters that are not in your party even though all of you are exactly at the same place. good job.
all WRPGs use both methods here and there, but there is no doubt which is superior and which is a lame unimaginative attempt to force you to replay the game.