Raising some issues

[GreenArcher]

Personally, I'm glad it's a small world. For once I can spend a majority of my time actually playing the game.

What's that? You want to kill this monster? Enjoy spending 30 minutes getting there! No thanks.

[Black Nova]

I find the main problem with PSO2 is simply the way the game progresses. In PSO1 the progression was quite linear which was nice because you didn't have to replay the forest 3-4 times to get to the caves. In PSO2 you may have to do a mission 5-6 times to finish all the COs to unlock a new area. This leaves the player feeling bored because they are forced to do the same area several times instead of just moping up the enemies and moving on.

[ShinMaruku]

COs need some slight redesigns I will agree. Also they need more things like the special events rather than just stacking ship when they occur I think such things should be unlocked.

[gigawuts]

CO's that scale rewards with difficulty activated on would be good (i.e. rockbears from hans could be unspecified rewards until you kill 1 rockbear on normal, then it's normal until you turn it in or reset it to activate on hard for better rewards).

There should also be optional sub-objectives, and alternate methods of completion. For a game made in 2012 it sure makes a lot of 2005 mistakes.

[ShinMaruku]

CO's that scale rewards with difficulty activated on would be good (i.e. rockbears from hans could be unspecified rewards until you kill 1 rockbear on normal, then it's normal until you turn it in or reset it to activate on hard for better rewards).

There should also be optional sub-objectives, and alternate methods of completion. For a game made in 2012 it sure makes a lot of 2005 mistakes.

Sega's mindset is back in 2004

[Syklo]

Which brings me to my next point, this game has a much more "vertical" gameplay than most other action-mmos; jumping plays a huge role, since every offensive/defensive action can be used in the air, enabling aerial combos for close ranged classes. Also, hunters cannot reach flying ennemies otherwise.
Some weapons are actually more efficient when used exclusively in the air, like daggers or launchers, and arguably mechguns.

Probably the biggest point for me. I don't get why games like DN and vindi lack aerial gameplay, if any. At least c9 had SOME form of "vertical" gameplay so I liked it much more than the former 2.

Whatever the "issue" is, I'm still enjoying this game.

[Cyclon]

Okay, you're obviously not looking into specifics there, but from what I've seen/played, Vindictus is the only one that might be truly similar. I'll try playing it myself so I can tell you for sure.

Yup, out of all the games in your list, Vindictus is the closest to PSO 2 imo. I wouldn't say they're the same gameplay wise though; then again, maybe that's just me.

Edit: just in case, haven't played Dragon Nest. Just watched videos, didn't seem that similar.