I could accomplish anything I needed to with the IL2 FMB, the only thing I felt I was lacking was random triggers and the ability
to cut and paste things. Air combat missions are not THAT complicated as mentioned above. You need to tell the planes where to go and when, and who is going to show up and when. Objects should be easily accessed through a menu. Same with ground units. All this can be accomplished within a fairly simple and intuitive user interface.
I disagree that the IL2 mission builder "wasn't that good" on the contrary, it was easy to use and powerful enough in most aspects.
I think it was quite excellent, though lacking in some areas compared to Falcon 4.0's mission builder.
The original Falcon 4.0 mission builder is another example of a powerful, easy to use and intuitive piece of software.
It's fine if a piece of software is powerful, but nobody cares if the time needed to learn it makes utilizing it prohibitive.
IL2's mission builder allowed me to concentrate on staging, timing, atmosphere, effect, immersion. There's a lot to be said
for that. The result of IL2's mission builder is that we had a TON of great user made content available. I created a load of
online CoOp missions that I hosted myself quite often. The ease of use that the IL2 FMB offered allowed great, mission oriented CoOp play, and we were able to create at least a few new, high quality, highly detailed missions weekly.
Aside from CoOp missions, I myself created the "Liberation Skies" offline campaign which became quite well known during it's heyday.

I peeked RoF's mission builder, and the word "bloat" doesn't even begin to cover it.
It needs a rewrite if we're ever going to see the kind of user created content that we did with IL2.
In any case, I'm glad at least a few people have time in their lives to crack it. I wish I did.
Cheers
Gambit