I'm also getting a Chopper developement vibe from this arc. Because of the mad doctor deal etc.
It's true that Chopper has already evolved a great deal all by himself, on the courage departement for example. Like how he started like a complete coward in Skypiea, with the "save me attitude", then becoming quite the courageous little fellow through his fight. Courage that he kept, if not improved through W7/EL, even ending as a rampaging beast.
And now, Dr.Hogback offers possibilities for…medical developement?!
There's so much stuff he could learn from another doctor (assuming Hogback's responsible for all the funky creatures on the island).
Just from what I can think of right now, there's so many possibilites. Chopper doing transformations on Franky anyone?
I was also thinking Chopper might finally find, like, a goal for his journey.
He wanted to travel and see the world at first, and he's doing it now. Gaining a more specific goal now that he's been travelling for a while would be nice, no?