I think there should be more features that assist group play, beyond things like the dungeon finder.
I'd like to see mindless PvE content queued up like PvP.
More along the lines of a CoD style queue.
Something like Dynamis or even a tower defense; or waves of enemies that takes 15 mins or less to complete.
I think group dynamics can also be introduced gradually in mini tutorial instances. But with any number of people 1-6.
Here's how it would work:
You and an AI/scripted partner enter the instance and it would teach you about skill chains, combos, hate and placement. Conversely you can use a real partner/random people with contextual directions.
Eventually there'll be 4,5,6 people in a group and you get an achievement score or item on how well you did.
Gw2 had a lot of cool combo abilities like some AoEs and archers lines of fire, but it was too impromptu and not purposeful enough.