Didn't get to play it all tonight, only a few things, so my first impression is very brief.
Upon installing the game, I immediately made a new save in Isla Paradiso, created my Sim and gave him the two new traits, and his LTW was Hotel Mogul (I think that was what it was called). He moved into a custom houseboat, which immediately set sail. Playing in the boat was fun, my fears about the camera pulling away and having to re-render the contents of the house were unfounded. I'll be moving in someone like Robin from my Dynasty or Max Skills to tinker with the boat engine and make it faster. The boat seems slow to me, it took two hours to travel a fairly short distance.
I bought a private lot, converted it into a hotel and promptly sold it, because I wanted to play more with the boat first. The hotel concept seems really fun and thorough, but I haven't played it beyond building yet.
I sent my Sim off to discover an Uncharted island, he seems to own the entire thing. I want to discover a larger island, see if he can build a house on all of it.
I also messed about when diving, I want to play more with it, it's a brilliant idea. Apart from teleporting from the dive lot to a nearby island, I've been glitch-free so far, which is nice compared to some of the things I've read.