I had the same thoughts as kja regarding the location of your hotel. To each his/her own. However, you could stay a bit more north (Tulum, Akumel, PDC, etc.) and visit Tulum and coba, but have plenty of time to enjoy the beach. If you wanted another ruin, you could fit in Chichen Itza before heading south. Not sure what the water is like in Feb, but in addition to ruins we have enjoyed the beautiful water for snorkeling, taken a catamaran day trip, and ferried over to Cozumel.