Frequent BVI vusitor here.
There are so many great experiences throughout the BVI's, but as a ship visitor with a limited time frame, you should base it on what your interests are.
First, FWIW, the Baths ARE a great, very unique experience. Unfortunately, yes, when visited with cruise ship excursions, they are crowded and IMO, not fully experienced/appreciated. There is also a certain amount of physical effort, my wife (we are young "seniors" - never thought I'd have to say that, lol ) with a bad knee and back is unable to go through, though when chartering there, we can visit the outer area and beach by tender. Not really feasible off the ship unless you find a private vendor.
As a pp states, snorkeling by the Indians is great. Again, that's if you're a snorkeler. Otherwise. . . .
For first-time visitors with
DCL, a great excursion is the Tortola by Land and Sea. It is a combo of a power catamaran overview of the nearby islands and the Sir Francis Drake channel, and an open-air bus tour of a great portion of Tortola. In the past, the caramaran left right from the main dock area of Tortola, and left you over on the West End, near shops, Soper's Hole marina, and Pusser's bar / restaurant. Unfortunately the West End suffered a lot of damage from Irma in 2017. When we were there this November, the Land and Sea tour was adjusted to be a round-trip to the main dock area of Roadtown. They claimed that the West End was going to be operational around January, but not sure if that will be the case. No matter, really, you can visit the Roadtown outpost of Pusser's right across from the parking lot where you catch the open-air bus if having a Painkiller is on your list.
If you're lucky, you'll catch the catamaran with David as your guide. Super knowledgeable, personable, and funny.
Score yourself points by knowing that, in the Islands, they pronounce his name Day-wid.
The bus portion will impress you with the switchback twists and turns both up and down the trip, with constant great views around every turn, occasional photo stops, and hopefully a stop at one of the small "lookout" bars for great photos as well as a Painkiller... . . You see my preferences, lol ?
Anyway, that's my input for now. Dedicated beach afficianados can find stuff up their alley as well.