After reading your post and the reponses I want to say I don't think you should worry one bit. Your trip planning job is secure.
It is the most wonderful little island. My husband picked GT last December and we went in March 2006. After having all of our reservations booked, we did what you did, and researched it. Based on most of the stuff we read, we almost changed our trip. That would have been a huge mistake!
We did stay 2 nights on Provo (just o.k.), and shortened our overall trip from 14 days to 10 based on the negative comments we read on the "boards". Well, I could have stayed 14 days plus on GT. The water is the most beautiful blue and the topography of the shore to the wall is incredible. The flight from Provo to GT is so unique. We met great people. What more could you ask for?
My husband and I were looking for similar things, a laid back island, reasonable diving, relaxation, and an off-the-beaten-path kind of vacation. This island was so safe. We met the greatest couple and we can't wait to hook up with them again for another dive vacation.
We stayed at Manta House, which is in the hub-bub of all the dive shops and little restaurants. Deb (the mom of the owners) escorted us around at times and really helped us find restaurants and such to try. She recommened Bohio as one of the best restaurants on the island. We rented a scooter and tried it. It was awesome. But we thought all of the food was awesome, and really, the prices are not that bad. Service is slow though, so don't wait until you are all really hungry. It is slow most everywhere. But that is the CHARM of being on a remote little island and feeling the pace of the locals.
We didn't rent a car, only that scooter on our last full day. We would have rented it longer knowing what we know now. There are all these little places to check out, snorkel, relax, etc...
We dove with Smitty at SeaEye divers. He was a good guy, it was a fun little operation. Nothing fancy. Oasis is a little fancier. But honestly, they all seem to be good acquaintances - no big competition. The ocean is big, but it seems like you see them all as you head out to sites. Dale @ Oasis has fancier equipment, more boats, a little fancier dive shop and such. But boat diving is boat diving, you need a good dive master, air, and what else? They all seem to do the job.
The Bohio looked like a nice place to stay. The cracked walls would be something I would myself find charming. The food was excellent. Cows walked by on the land between the resort and the beach at near dark. I mean, where else can you experience that? The only drawback to the Bohio is that it is a hike to "town". The grocery, liquor, restaurants, etc... That makes it a little more secluded feeling, which I'm sure adds to the resort feel they are trying to portray. There was a complex near SeaEye that could house that many people. It is at the end of the street they call barefoot alley. It is within walking distance to the grocery, liquor, restaurants, etc... If you have vehicles like you said, it wouldn't be a priority to change just b/c of that but that would be your only other option.
There is trash, mostly on the other side of the island. It washes up. Seems like an endless battle. Islanders don't seem to be those pride of ownership people like Americans seem to be with their homes and such. Plus, there is no doubt their funds are limited. I found most times we could ignore it. It does not impede on having a great dive vacation. Everyone we met in passing was nice. I never felt scared.
The reefs are experiencing bleaching. That is going on in various places around the caribbean. We did see turtles almost every dive. We saw whales from shore. The other people we met did encounter dolphins on a dive. I have not dove in that many places, only Bonaire, the Keys, West Palm. The diving was nice, but not exceptional. But the friends we made and enjoyed topside made it all worth it. This was their 4th trip to GT.
Mookie Pookie is supposed to be awesome. Be sure to have grouper at the Water's Edge. Beer is about $2.50 a bottle from the little liqour store. No one will starve, there is plenty to eat. Things are not that hard to find. Everyone knows someone that can find something. It's all good.
I know people that would hate a vacation like this. But your key words were laid-back. This is the island for you. It is not 3rd world, but it is exactly what you expect when you envision island life.
I hope you have a great time in GT. I can't wait to go back!
p.s. the cruise ship thing hardly affects the island. those tight-*** lazy traveler's will rarely get off the ship to go spend some money in town. It's a joke. It will be a long time before it adds anything to the economy which I'm sure was the bill of sale they were sold.