Ideas to get fleets out of the shadows:
1. Attacking fleet may not have more ships than defender and higher tier. For example I get my fleet in wof room with a D, D, C and B tier ships, attacker should be limited to 4 players and B tier max
2. Defending fleet strength by number and tier of ships: strength in points* by tier F=2, E=3, D=4, C=5, B=6, A=8, S=10. So the D,D,C,B above will worth 19 points, I can attack with an S and an A (18 points) or 5 E tiers and a D (19 points) or whatever i think is best
*points per tier indicative - need playtesting to create truly competitive not favouring high, mid or low tiers
One of the above, combined with points given for being active should address both the inactive fleets issue and the fear of getting overpowered by a fleet entering with overwhelming strength