After spending a night in the Fort Lauderdale airport, I can confidently say that it’s better to fly into Miami for cruises departing from either Miami or Fort Lauderdale.
I’ve flown into Miami International for a cruise previously and there are many hotels near the airport that are both cheaper and more convenient, especially for wheelchair users. For example, at MIA there is actually a hotel in the airport itself and several very close to the rental car / train / bus station.
Personally, I’d opt for that convenience because it saves the hassle of having to find wheelchair accessible transportation to a hotel. In addition, it makes the task of getting to the port on a cruise shuttle easier as well because you can catch it from the airport nearby.
You Should Go Anyway 