First of all, i consider myself a dedicated carrier player, altough i have found interest in Destroyers and Battleships aswell.
In my opinion the biggest reason why carriers get so much negative feedback in the forums, is because almost every competetive skilled player, who seeks to achieve the greatest amounts of experience and the greatest chance for a win, currently rolls with the offensive strike-loadouts of the carriers. Since dealing staggering amounts of damage to the enemy fleet is simply more rewarding than protecting your own. Both in Fun,exp and credits
This ultimatively has the side-effect that carriers seem to do overly well damage-wise, but that's just because there are no enemy fighters preventing their bombers from striking.
I would LOVE to dig up my defensive Fighter-Loadout with my carriers and give the enemy CV a hard time, but even with monstrous amounts of planekills, outstanding AA cover performance, i just know that i will end up with average exp and credits. This is just demoralizing. So i end up switching to strike-loadout again.
Another problem is the Ammunition on Fighters. My Lexington Fighter Squadron can kill 1 Squadron of Torpbombers and is almost out of Ammunition, so i have to return them, costing me about 90!!!! Seconds of time where the fighter is absolutly useless. in this time the enemy CV just launched another torpbomber squad, and this time there is no fighters available to disrupt them. So you failed your AA job, and since ur attack capabilities are extremely limited, you are basicly a useless member of your team, with HIGHLY restricted influence on the game.
My suggestion to motivate players for a defensive carrier role is to increase the rewards for shooting down planes, and fixing the ammunition values on fighters, especially in higher tiers.