It's not me, but I know a "talentless mouse wielding fluff driver" who'll sink 3 cv's with the same formation of Lanc's. If you check his ranking, you'll see that it's about 300, or less. Seems to me that it takes a lot of talent to get a rank like that.
As for the hardness of the cvs, I think they are unrealistically tough. In reality a 500# bomb on a deck would render it unusable for hours if not days. Not so in this game where the elevators never ever get knocked out, all burning wreckage is immediately doused with Halon and transported to a recycling facility, and the deck is made out of something I wish my panzers were made out of.
The cv's are defended with epic battles because there is a risk of loosing them. I doubt if there would be the effort to save them if this was not the case. I also suspect that if they were made even more unrealistically tougher the incentive to attack them would be reduced.
Those of you who love the epic cv battles, why do you want to wreck it?
As for keeping them 20 miles offshore, isn't that what the shore batteries are for? Why force that in the game?