Tell me what you want AT your hotel. Do you want/need a pool? Do you want a more private beach area? Are you willing to stay right in town, right in front of the dive center, and from where you can walk everywhere, but will not have much privacy on the busy beach at that spot?
I ask because I stay at the Mayan Princess, and dive with Amigos del Mar. Have stayed at Sunbreeze Suites in their previous incarnation. The pool is quite small but a couple of weeks ago there was a guy in measuring it for expansion, so woudn't be surprised to find the whole patio/pool area is a construction site right now. Very bad for JamBel's, the restuarant on site.
You could stay at Paradise Villas, which has lovely grounds and a small pool, but is also on a busier portion of the beach. This is not a significant matter, since the sunbathing can be done on the grounds. You could dive with Ched's shop, Captain Ron's Reef Adventures. Perhaps if it is available Captain Ron can offer you a special package deal on his condo and dives at the shop.
Could stay a couple other places and dive with Chuck and Robbie's.
Could stay further south, and still be able to easily get into town, dive with whomever you want cuz they will all come and pick you up at your hotel dock.
Could stay at Spin Drift and dive with Rudy and his staff, at Island Divers.
You could book one night somewhere and then try to do a walkin rate at a chosen hotel, but hey, why not just email a couple of places of your choosing and see what they'll offer. Now that Easter is over, probably more than a few rooms available at most places.
Should be no reason for you to have to stay anywhere but on the beach.
Even Hotel del Rio gets some positive nods. Looked to me like they've been fixing up the place.