I love the 4th and 5th movies of all the rest. However, in case you didn't watch the old movies, you better do. It's worth it.I don't how they'll pull it off then but it's going to be good hopefully. I don't know how the rest of the movies have been but Strong World and Film Z were amazing. Even though a new movie is good, I kinda want the news to be related to the OP manga. Toei has a lot on their hands if a OP movie is indeed coming out this year.
There is an OVA of One Piece came in 1998, just before the 1999 TV-series. Funny thing, the first voice actor of Zoro was Wataru Takagi (Bellamy).