My suggestion is simple:
-More exp for all if you win.
-Less exp for all if you loose.
Example 1, as a reference: a BB5 making like 150k attack if he wins the GB he gets like 60k exp. Making the same attack he would get 45k if he looses the battle. Instead 60/45 make it 80/25.
Example 2, as a reference: a PCV making like 20k in planes shotted down if he wins the GB he gets like 45k, if he looses he get like 30k. Instead 45/30 make it like 60/15.
The same with submarines and smaller ships.
That way, for example, FW CVs would be more worried about giving light than shotting down planes. BW CVs would be more worried about finishing ships than getting attack bombing a BB6 all the battle and not sinking it. SSs would be more worried about facing other SSs than evading them. BBs also would be more worried about playing well because in the win/loose goes the exp.
I think more reward/punishment if you win/loose the battle will bring us more beatiful games with actual teamplay, motivation for people playing better, motivation for improving their gameplay if they want to lvl fast and game will be more skill-based and less "arcade" than it is now.
Recommend if you like.