This game was developed as a followup to Phantasy Star Universe with the name of the game not really playing a role in the overall design decision. In some alternate universe, this SAME game as it is would be called Phantasy Star Universe 2 and we would be asking for a return to PSO1 in a similar way to how right now there are those who want a proper PSU2.
Now then, about this issue... I would argue that PSO2 is the most streamlined game in the series and definitely one that's aged better. As the developers admitted, the issue with PSU was that it was designed with a Single Player game in mind without taking into account the effects this would have on the Multiplayer. PSU is not bad, but its seriously rough around the edges (though I won't deny that PSO2 is also rough around the edges in some places... like the way it handles the Story Mode), a mishmash of good ideas that just aren't executed to their full extent.
Overall, as many others have suggested here, do try playing with others and learning the game's dynamic. I would throw an extra suggestion of trying to directly compare the game to PSO or PSU, trust me it will make things a lot better to deal with. I imagine a lot of the nostalgia related issues would be avoided if PSO2 was called something like.... Phantasy Star Galaxy or Phantasy Star Multiverse, building up on the successor naming scheme between Online and Universe xD