I had an idea for a doom mod and couldn't help but think it'd be perfect for you, considering your modding expertise and how great Mr. Friendly turned out.
I was thinking about how neat it'd be to see all the Doom levels in a pre-disaster setting. No demons, no hell, no satan, just UAC workers and scientists going about their work, and you can talk to them about what they're doing, like as an inspector or something.
The same could be done as a post-disaster setting, with you watching over the rebuilding effort.
Perhaps Hell just so happens to be empty or devoid of any hostility and you can see what the scientists do as they explore?
or just maybe, the demons are only hostile to Doomguy, and are friendly to everyone and everything else, yay for human/demon relations.
So this could probably be a branch of Tourist Doom or Mr. Friendly or both.
I hope you enjoy my idea and might even consider making it a reality.
Thanks for reading