4. The way that party dialogue works means the game has basically no roleplaying to speak of. You create all four of your characters, giving them unique classes, alignments, backgrounds, and a few personality traits. But when you talk to NPCs, you are basically given four options - one for each character. That means that there's really one, and only one thing each character can interject at a given time. The characters are all 100% voice acted, which is nice in a way, but there's simply not quite enough flavor put into each one to give a real idea that each of your characters has a unique personality. I mean, my mage chimes in with history/arcana lore from time to time, and people recognize their co-religionists, but my Paladin has said pretty un-Paladin things as well.
A lot of the personality traits overlap one another, yeah. I've been trying out various combinations to try and see if I can come up with four very distinct and different personalities.
One note though, in 5E Paladins aren't bound to be LG anymore. You can have a Paladin who's chaotic, neutral, or even evil. There's no such thing as a "Paladin personality" anymore, since they're just people who are warriors of their god. And if their god is a jerk, well, the Paladin can be a jerk too.

That said, it WOULD be nice if some of the dialogue were tilted in alignment directions a bit more.