I'm just going to say this: We cannot, and I mean, NOT think of our selves in the case of where we believe it should start. The moment you take yourself into consideration where you want it, you pretty much lose right then and there. We have to, as fans, think of the bigger picture, what would be the best for the series. We can't think "Oh, I want them to play the newer episodes because I'm there", or "It's going to take too long to catch up". We can't think this.
As someone has pointed out, it has been 5 years since One Piece has last since seen airwaves on regular Television, not counting TV Japan's airing. There is a big gap in between when the casual viewers have since seen the show last time and now. As a result, they have possibly moved on or sought other ways to view the series. As a result, I feel what would be best for the series as an overall whole, is the fact the series should get a clean slate and reintroduce itself to everyone. Which would mean restarting the series from Episode 1. There is, also I should point out, still a misconception that 4Kids still has the license, as looking over on Twitter and some other places, so this would also be a good idea to show those viewers this is not the same company by starting at the beginning.
Another thing is, if we start from Season 4 or midway through Skypiea, we still have a problem of possibly returning viewers (if they exist) and new viewers tuning in and being completely lost, for one reason or another. There is a chance they may seek out legal (or illegal) means to try and "catch up", but there is probably a bigger chance of viewers giving up on the show immediately and deciding not to check it out, simply because it didn't start from the beginning. What is important is to build the property from the start with the casual base and go from there. It's just, personally, a stupid move to risk losing new viewers and potential new fans by starting in the middle of the series.