@Ivotas:
Oh yeah, this is what I wanted to ask you on that matter. Is there certain tasks only specific characters can take care of like in RtL? Like Zoro beeing the only one to break certain obstacles, Chopper jumping that high in Jump Point to reach plattforms no other could or Robin being able to open rooms thanks to her skill to read ancient texts? That´s actually the fun component I loved about RtL and why is worth to go for 100%. Does UA have something of that sort?
Well, kind of. Ex. Only blades can break the long ivy. Therefore, only Zoro, Robin (she throws knives), and Usopp (caltrops) can break them.
Also, the different sizes come into play. Franky is the largest so (for some reason) he can jump the furthest. He also has the most HP. Chopper is the smallest and can maneuver around obstacles quickly. He isn't very good at catching bugs on trees because of his height, but is one of the best at getting the flower ones. He has the most SP (rumble ball is like a GOD. Jump point is only there for fun :\ ) All characters usually refer another character to do the task that only they can do (Only robin reads Ancient text, therefore all characters ask her to read the stone monuments in the game for them). There is unique dialogue for characters depending on what you do (Franky Vs. Spandam, Luffy vs. Shanks, etc.)
Mostly, they all seem to play the same to me :S
I think the reason they make you level characters up is because you prbably wouldn't play as some of the characters (Robin + Franky are the best characters in the game. Sanji and Zoro are good as well. The other characters have good moves, but aren't very well rounded)