One of the things that sucks about PVP and can dissuade people from raiding is having to wait 2 hours for your folks to get home if you don't want to leave an empty compound.
My suggestion: introduce an upgrade to the Deathmobile that will instantly speed your guys home after a raid or scavenging, but won't allow you to actually send them on a raid or mission for a period equal to the regular return time. They will have to rest at the compound for 2 hours after a raid, for example.
With such an upgrade in place, you could play the game and then walk away from your computer, rather than doing what most hardcore raiders do, which is idle / occasionally go to the browser tab for a couple of hours until their guys are home before logging off.
It'd make things a lot fairer because it'd mean folks who can't be at their computer all day would still have the opportunity to raid and not have to leave their compound wide open to attacks when logging out.
It'd also help solve the bounty problem of leaders not being home, which is something many people hate, and generally would make it more fun and challenging. I hate scouring a target list for hours, sending out a full team to raid and finding an empty pound. Sure, it's a free flag and resources, but it's boring as heck!
Finally, you could still spend fuel to speed up their recovery time, I guess, if you wanted to raid/do missions before their recovery period is up - so it wouldn't mean any appreciable loss of fuel spending on return times. The upgrade itself would probably cost fuel, so overall there may be a rise in fuel spending as a result.