1.add shore guns to all bases
2.make cv flak dangerous to all players, not only enemy.
3.reduce cv rebuild time, when sunk.
4.add enemy ships distance indicator to shore guns, since they had the stereobinoculars in ww2 (if i remember correctly). CV would be piece of cake to shore gun in RL, when its in range.
Then you can make cv:s come closer to shore.