I use it occasionally to create custom missions for testing/training on specific scenarios. For example, instead of having to start a free flight mission to train my bombing techniques, i made a custom mission with complete take-off,cruise, attack, RTB and landing phases, plus some actual targets on the ground and a bit of flak to spice things up.
As for the difficulty of it all, maybe it's a case of acquired habits. I didn't know anything at all about the old IL2 FMB until i convinced a friend to get back into flight sims after a long break of his: i had to make a simple coop mission for us to fly in IL2:1946 with a bit of easy yet diverse targets to try out and a bit of AI action on the side to spice things up, so that i could get him a refresher course on the basics.
I went to that community website (
http://www.il2-fullmissionbuilder.com/) and followed the video tutorials and i had one up and running in no time at all, us flying a couple of tropical Spit Vbs on the Sicily map with a friendly convoy crossing the straits, an axis coastal battery firing on the merchant ships and the lead escort zig-zagging while returning fire. The aim was to bomb the coastal battery and then shoot down two Ju52s that were executing a supply drop over the same area. I think it took me about two hours total from knowing nothing to getting that mission done.
That being said, i didn't have any trouble at all switching to CoD FMB and i think i know the reasons for this:
1) I didn't have to break long time habits of doing things a certain way with the old FMB because i hadn't touched it up until i had to make that coop for my buddy during the last winter.
2) I didn't need to use 100% of the features in the old FMB so i certainly haven't used yet the extra ones in the new FMB either.
Documentation is indeed a necessity, but i think that anyone with a basic understanding of the old FMB can certainly use the new one for some quick and dirty mission editing. Most of what's in that tutorial website i linked still applies to the new version after all.
The main differences lie in the area of scripting, radar reporting contacts (needs stations and a defined grid) and the fusing of coop and DF into a single MP mode (spawn points now are actually objects you can place on an airfield).