I don't really understand how a checkout dive assesses a divers skills. I didn't do a checkout dive in Cozumel, but our dive op did easy dive first, and then progressively more challenging (but still pretty easy). In 11 dives, my mask never needed to be cleared, my regulator never left my mouth. How did these dives show my skill at anything other than not crashing into the reef, holding a safety stop, and my ability to equalize/descend?
It seems like if an op wants an assessment of a diver's skills, they need to have them demonstrate them.
Think about that a minute.
First of all, congratulations on never having to clear your mask. I have a great-fitting mask, and I still have to clear it at least a few times on every dive. If you are having a little trouble with that, it's pretty much just your problem. Regulators almost never come out of anyone's mouth, and when they do it usually just drops in front for easy recovery. Dive operators are not worried about those skills.
What they are worried about is your buoyancy control, crashing into the reef, making an unexpected uncontrolled ascent--just generally looking like you are confidently in control of your diving. That tells them whether they have to worry about you or whether they can take you to a more advanced site.
A few years ago I went on some dives in Cozumel with an operator who had only one boat, one DM, and no requirements for checkout dives. It was an operation that advertised itself as doing more advanced dives. The first day there was only one other guy and me, and we had a great time on great dives. The next day we were joined by another couple. From the start it was a disaster. The wife looked like she should not have gotten through the confined water portion of the class. We spent the first 5 minutes of the dive in a sandy patch watching the DM give the woman a buoyancy lesson, the kind that is done during PADI confined water dive #2 now. Then when we tried to do the actual dive, the DM realized he needed to hold her hand the entire time. This was on a dive scheduled to go to 100 feet. You can bet we skipped all the intended swim throughs. The second dive of the day was the same--the DM held her hand throughout the entire dive. I sure wish that operator had the capacity to require a checkout dive. It would have made the rest of us much happier.