Disciples of Sobek(Flight Eater)
Seeing as a Fleet (aboard a MS) cannot be attacked, they in turn can not attaack others ---ie this house cannot conquer planets.
Flight Eaters, of course, will not be able to fly without angering their god...so it is in fact your own crew who -in fear of gods- does not engage in such flights.
UPDATE(the next day): OK - so, massing planets was an issue if target could not destroy the fleet back. But no planet acquisition also an equal issue...SO.....
The ability of those in the house to attack planets is back. BUT the chance that the MotherShips do NOT engage (but turns still used) is now 80%, leaving 20% of the time it works normally....
Also: 20% of the time, defender and attacker MS WILL engage in normal battles.
This should allow everyone their desired actions, with a bit more risk than before, and potentially costing more turns for retaliation, but not impossible.
Looks like it got changed so that it's not really no MS, but it's mostly not MS. Seems better to me since those in can still steal planets, but those out of it can still mass fleets (and motherships too now it seems).