Let's just keep something in mind here...
The purpose of FSO is to allow squads to fly and fight as squads. That's why the objectives are publicly published and the targets are known to both attackers and defenders. It's also why a target needs to be attacked within the first 60 minutes - to ensure people get to fight.
Sure, sometimes a group is stumbled upon and wiped out before reaching their target, or they hit the wrong target, and defenders are left circling for two hours with no enemy encounter. But let's not make it worse by obscuring the target area so a strike group has to divert to a "secondary" target...again leaving the defenders a boring night of circling a target that will not be hit.
The whole purpose of this discussion is to find a way, without enforcing artificial rules, to keep strike packages at a designer's desired altitude for his event. I think the best solution, albeit a little more work for the designer and setup CMs, is to have custom clouds and winds to make going above certain altitudes "undesireable" for bombers - either because of a cloud layer or winds aloft (not just a max downdraft) that would force them to work hard to stay on track and actually see the target during the bomb run - which would at the same time allow escorts and defenders the opportunity to position themselves for a chance of success.