Marianne (non-diver) and I have been to both and enjoyed both. As you know from your experience the diving is different. If photography is a big part of your dive trip then it can be more challenging with the currents on Cozumel. But if you frequent this sub-forum you also see the beautiful pictures that are taken on Cozumel. You can look at it as an opportunity to develop your diving and photographic skill set. When we went to Curacao we stayed at an AI and while it was very nice with a good beach it is not something we would repeat. We did go into Willemstad several times for dinner and were impressed. Why we choose Cozumel as a regular destination (although we do try other places) is actually not dive related since I would dive either place at the drop of a hat. We stay near town and find Cozumel and the city of San Miguel to be an exceptionally friendly, walkable, and safe place. While I am diving Marianne walks for miles along the waterfront and in the town and has never had a negative experience. We chose a different restaurant every night and have developed a list of favorites that we frequent but we make it a rule always to try at least two new restaurants each trip. We find the people of Cozumel to be genuinely welcoming with a positive outlook on life. Cost is also a big factor for us. We can do almost two trips to Cozumel for what the cost of one trip to Curacao would be for us. Naturally that would differ for you since airline, hotel, rental car need, and many other things would factor into the equation.
Pedro-Pablo, the main DM, at Blue Xt-Sea is one of the best.
Enjoy your trip and safe diving.