I think there's enough to see. The only thing to be mindful of if you want to do four dives a day, many of the Broward and Palm Beach County dive shops only run boats in the morning Mon-Thursday. Many will do morning and afternoon trips on Friday during the summer and will run Sat and Sun AM and PM dive trips year round. As afternoon alternatives, you can beach dive Lauderdale by the Sea in the afternoon or Blue Heron Bride if you're in Palm Beach County and the tides are right.
If you're coming for a week, try diving Jupiter, WPB, Boynton and Pompano/Ft Lauderdale. Lauderdale and Jupiter are only 60-70 miles apart so you can work your way down (or up) the coast.
My favorite shop is Jupiter Dive Ctr in northern Palm Beach county but have also had a good experience or two on Scuba Works boat. In WPB there are many boats, Narcossis, Sandy's Sunday, Jim Abernathy are a few. In Boynton there are also a number of boats, Underwater Explorers, Splash Down and others. In the Broward County area, I like Pompano Dive Center, South Florida Dive HQ and Scubatyme. Most of the diving is deeper than the shallow reefs in the Keys, though Pompano and Lauderdale by the Sea have a lovely shallow reef line that is enjoyable to dive. I especially like the shallow Coppenhagen wreck and surrounding reef. Gold Coast Scuba and Force-E are two good shops that don't operate their own boats but will get you on other operators boats: just describe the sort of dive you want and they'll find a boat for you. Gold Coast also has a dive club that does a lot of beach diving. You can join it and meet other divers. Enjoy your trip.