I've read that many imperials are not taking part in the current tournament.
Their target is perhaps to fill up resources after they've been attacked by "us" rebels.
The other way round it should be very difficult for them to take loot from my base and not get at least one star.
I lose some medals but get some protection for that. (I am not playing all day
Getting medals back has not been a problem for me (I am at about 0.07% in the tournament currently). It just happens very rarely that I completely fail an attack. This may get harder in Level 7.
It would be nice if you also post your level 7 layout when you feel it's ready. It will take roughly 2 weeks for me to get there. Probably still some time to look how my current layout does against "repaired" AT-ATs when the fix arrives.
Perhaps I will then move to your layout on level 7.