Although I only ended up doing beta testing on this effectively late on, I was following the game for quite a while (which is why it's getting mega <3 from me) so I'd like to hope I know a fair amount of how the game has been developed.
As many people have stated, the game seems very obviously split into very different sections. This initially wasn't the intention from the beginning, yet the beginning was very different with this game...
Jump back in time 2 years. A small team called Flying Labs Software wanted to make an online game based in 1720 where you went around sailing old fashioned ships.
That was it. Nothing in terms of human avatars existed. No graphics, no swashbuckling...
It was around 6 months into the closed beta when FLS decided to scrap that idea, in part. The players from back then were asked about the game content and the general concensus was that the game was certainly lacking something. For the sake of comparison, the ship combat system was basically (apart from minor adjustments) is the same now as it was then. The ship-to-ship combat was in place (although no boarding) and you could do the big PvE part of the game which was the whole port contention thing.
So, 6 months into a game design, FLS scrapped the original release timescale and went right back to the drawing board. More things were thought up, the human avatars and then everything linking to that were all thought up, coded, graphics designed in the existing system and then let loose.
I'm not saying that in anyway to defend how it is right now, as even FLS have stated that the first thing to be improved will be to work on the swashbuckling side of things. However, they're happy to go ahead with what they've got now rather than take even more time on an already lengthly pre-release production period of 2 years.
Equally, the port designs are ALL going through a level of massive development. Again, all of this had to be added. Only recently, Tortuga was reworked into a much larger and realistic envirnoment.
Oh yes, and then the economy system too, which all had to be created as part of this...
I could go on but I think you see the point.
Yes, the game is still going through massive changes. In the time when I've been actively taking part in Pirates beta testing (only the best parts of 3 months) I've lost track of the number of updates that have been done to the game. Even now, many of their staff are working on updates, hell there was a patch only days before the end of beta yesterday (containing a LOT of stuff)
So yeah, there's lots still to do before the game would be 100% finished. That being said, when was the last time any mmo went online 100% ready and it was never changed for any reason after launch? 
IMHO this is gonna be a good game!
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