Yes, yes it is definitely lacking. I'm really, really underwhelmed with this pack because I was expecting something like Island Paradise from TS3. My expectations were pretty high. Let me explain.
Scuba diving is a big disappointment. Why can't you go with your sim? Why can't you see the ocean? Really, all you get is to wait for your sim to explore the ocean that you can't see, and then you get a response saying "OH BOY LOOK WHAT YOUR SIM FOUND!!!!!!" Yeah, cool, but I would've liked to have GONE and SEEN the ocean with them.
And then we have the boats. Not much to really complain about them, but I wish that you could have multiple sims on a boat. When I first saw the boats when I loaded up the game, I thought you could have 2 sims on a jet ski, but nope. One. And the bigger boat. Nope, one. Again, not really a big deal but for an expansion, this just should've been there.
Mermaids. I don't really care for them anyways, but what I've seen from playing with them a little is that they're kinda boring. You can't do a whole lot from them. But I personally don't really care because I'm not that interested with them in the first place.
And there's just not a lot to do in this pack, really. I wish there were resorts, I wish there were house boats, I wish there were underwater houses, I wish you were able to also vacation to Sulani, and I just wish there was more to explore.
All that aside, Sulani is really beautiful. Over the top beautiful. The sunsets are amazing, the water looks gorgeous, the island itself looks phenomenal. The build mode and CAS, while a little lacking, has some of the best items I've seen. I love it all.
While it is lacking, I just love the vibe I get from this pack. The scenery makes me really relaxed and joyed. I feel like I payed just for Sulani, in my opinion. Everything else got boring quick.