I don't see how cbets can be such a big leak. If they work at least 50% of the time, they are +EV, which by definition is not a leak. Learning which opponents/boards to cbet is important, but even with all of this knowledge you don't know what cards your opponent has, and if he is generally going to muck if he didn't improve, then a cbet is +EV with one person and generally +EV w/ 2 people on non-scary boards. Opponents that play back at you a)with air, and b) with pocket pairs - these are the very important situations to watch out for, but they can be easily exploited when you do have a hand. But until you have a read on an opponent, a cbet is +EV heads up on most boards.