I liked it. I can see this series go places. It's no Fairy Tail, and Luffy's no Natsu of course.
Some predictions of mine:
This "Luffy" will have 2 brothers, and Daddy issues.
Thi Shanks" character will be one of the strongest pirates (him having 1 arm is deceiving).
Blackbeard WILL make an appearance of some sort in the series (it's about pirates, come on); I'm thinking a primary antagonist.
And, lastly, there will be a character who is behind everything and a character who is everyone. Oh! And some technique, begining with the letter H, G or Z, that everyone is said to have. :ninja: