I wouldn't mind if there was room for 6 in the party, but 5 would still be an improvement. As you say, a bigger party brings more variation. I doubt though that we will get a 5th party member as the whole game would thus have to be changed to fit that.
My basics are fighter/wizard/healer, leaving out the rogue since I don't care much for that class, and for my main character I either choose a fighter (toughest class) or a dragon blood sorcerer (high charisma, good for negotiations AND nice enough to have in a fight).
I also like to play druid, but I don't feel there is room for a druid in the current composition. One fighter (Lae'zel) + one mage (Gale) is not enough for my combat needs.