Yes and no. The betas we've seen have been far from what is supposedly in the final release. A whole faction was missing, none of the 'advanced' quest lines were in. Supposedly there are tougher 'legendary' quests and once you attain legendary status you unlock areas and new questlines. The Kraken wasn't in, and they talk about having special 'limited time only' events and questlines that will keep the world 'changing' and dynamic.
All that being said, I don't really expect all of that to fundamentally change the game in any way. Its not a game for you to go out and solo grind 50 skeletons for sails of +1 gooder, or to grind raid content weekly looking for top end gear. All the quests and shit in the game is really just an excuse to get you out on a ship with a crew of friends and start fucking off and having fun. Its a very different experience if you are used to MMO progression grinding. The point of the game is less to advance and more to just fuck off having fun and 'advance' as a side effect. Play this game with a beer in one hand and the mouse in the other, laughing your ass off as you shoot your friend out of a cannon straight into a cliff face just to see how far he ricochets, then laugh more as he bitches about it. That's the basic game play.
Play with friends or I think its going to be a really short lived game for you.
Edit: Possibly a more coherent answer. Our gameplay generally went like this. Get quest. Get in boat, head out to pick up the treasure. Along the way, find a sunken ship. Go explore it for a chest. Find the drunk chest. Laugh as it makes whoever carries it instantly drunk. Start to sail off and then laugh as he, being in game drunk affecting you with random movement, falls out of the crows nest and into the water. Make fun of him as we sail on and tell him to catch the mermaid that teleports you onto the ship. Then see sails on the horizon. Its a sloop, we are a galleon, so chase it. Spend 30 minutes or so chasing it and realize my crew can't hit shit. Watch one of them get blown off the deck by a stray cannon round. Laugh at him. Attempt a boarding action, fail. Decide to just ram them. Board, sink them and suddenly realize we're also sinking cause of damages so bail and patch in a frenzy while someone on top is trying to shoot their guy who abandoned ship to make certain he doesn't try and board us while we are repairing.
And the end of that, we laugh and remember we have a quest to go find a chest. Start sailing back off to get the first chest we started out after. Then we either get sidetracked again, or grab the chest and get a new quest. Rinse, repeat ad infinitum.