I had no problems with weighting or buoyancy before that first Cozumel trip, and I had done some drift drives in the past - including the crazy Washing Machine dive in the Bahamas - but the strong current in Coz was difficult for me and it took a little time for me to master it.
It must have been a really bad day. In ten visits and 150 dives there I can recall only two dives when I noticed a current. One when we zoomed over Paradise Reef and another when I had to hold tight while the rest of the group was harassing a little sand shark under a ledge. Otherwise I don't even notice the current.
There are so many new divers that go to Cozumel and have no more problems than new divers seem to have anywhere.