Details are a bit fuzzy but I broadly remember:
Comanche: helicopter flight sim that you can actually fly, decent (for it's time) terrain that you can actually fly nap-of-the-earth in and benefit from such tactics.
Comanche 2 & 3: pretty much more of the same with spankier graphics.
Comanche 4: hold on, this is more like an arcade game now - I want to fly low and slow, too old for quick reactions. Yuk!
Then, of course, there's the Doom III situation where the game becomes all-but-unplayable on average machines.
The only way editing can be made simpler to any great extent is to not have such powerful editing functions. We wouldn't want that. OFP is perhaps unusual in that Joe public gets a peek at what it actually takes to make a game like this work. If editing was simple (i.e. restricted) interest in the game probably would have withered a long time ago.
I hope BIS keep their feet on the ground and don't try to change the nature of the beast we have. There will be a marketing temptation to cash in on SF and graphical gorgeousness but, please, not at the expense of the things other games don't do.