On the subject of difficulty: Personally, I'm fine with it as-is, although it certainly wouldn't hurt the games accessibility to have easy and hard modes. Simple things like damage scaling, perhaps slightly more/less aggressive and fast enemies, etc etc.
But that's up to the Bit-Blot folks.
Personally, I would love the ability to crack open the base campaign in the editor, both for learning purposes, but also for the potential to create edited/remixed versions of the campaign.
I'd liken this to the excellent 'SMod' for Half-Life 2. Now, don't get me wrong, I love HL2. It's a classic, but SMod is a fun new take on the old content. It uses the original campaign, but with reworked enemies, placements, new weapons, and a somewhat more vicious sense of humor.
If you let modders choose to stick to the same structure and story, they can often do quite impressive things within the logical context of the game itself.
I'd also like to see some 'expansion' type mods, adding new areas branching off the original game world. Not every mod has to be a new world/level started from scratch. At least during the early days, it's often better to let modders play around with and rework existing content to learn the ropes, rather than throw them into a vast ocean of possibilities and watch them flounder and start projects which will only end up directionless and fizzling out.
Just my thoughts, though. Generally speaking, I like to see as much freedom and power given to modders as possible.
