Funny, but those are the same reasons that I still fly Southwest and do the bag drag. I finally managed to get all my gear in my carry-on and back pack (small, under-the-seat item). I suppose I could check the carry-on but to me checked bags are a PITA. What are the airfares like to CZM (COZ is the Dominican Replublic) ? It would have to be comparable (including ADO and ferry) and not hundreds more for me to quit the bag drag.
I would normally do the bag drag when the airfares to CZM are over $600 (usually $700+ on Delta from ATL). I found fares for $405 and booked it. My wife nearly lost her dinner on her first (and last) ferry ride. She flew back to CUN while I did the bag drag back. $405 is $50-$100 more than ATL->CZM, but so much easier and worth it - especially with the wife not getting seasick.