Its quite boring for the Attacker and Defender if there is no enemy in a Fleetwar, although members are online they are sometimes not set as the task force. a Hierarchical approach would provide more real Battles in fleetwar.
If a leader or officer could set a priority for each fleet member to participate in fleet war, you just have to pick the up to 10 available kaptains with decreasing priority
edit:
e.e.
Member Priority Online?
member1 priority_1 online -> fleet war
member2 priority_3 offline
member3 priority_2 online -> fleet war
member4 priority_4 online -> fleet war
member5 priority_5 online -> fleet war
member6 priority_7 online -> fleet war
member7 priority_6 online -> fleet war
member8 priority_8 online -> fleet war
member9 priority_9 online -> fleet war
member10 priority_10 online -> fleet war
member 11 - member 98 offline
member99 priority_99 online -> fleet war