Coming straight from pso1 and not ever(wanting to) experiencing psu, I think there is an issue in the party up system. My conclusion is that it's not only because of the variety of missions, which aren't alot really. It's also because the game's freedom offers people to play differently within a mission, so people don't join each other that quick like in PSO1, where it was always clear what the 1 goal was to everyone. Here everyone clashes so they have alot of reasons to not join each other sadly
One person likes to keep grinding, one person wants to rush, another is there just for a client order, another likes to explore and get to the end. I for example don't join neither the rush or grind games, which are the majority so I have to literally ask people at the lobby to join me and follow my lead, which has helped so far alot to boost my experience. Ezodagrom is always fun to play with too.
I do consider this kind of an issue so I hope they spice up the incentive to party up, and work so people do not clash. My idea was that when one starts a mission, you should be able to see some sort of cloud above the character in the lobby(or maybe something more subtle) and add a join option in the character quick menu. This would make it easier for people to wanna join someone, or for a player to get his party joined up.
Other than that, when I do get a good party, PSO2 seems like one of the best games i've played ever. Love the shit out of it. I just can't go back to pso1 anymore because of it.