I have numerous ideas.
Godworld - Immortal Combat - This would be one of those Massmouth 2 themed WADs with a backstory and numerous ways to play through. The backstory is fairly simple: two powerful gods-in-training quarrel and battle continuously, until one goes insane and starts destroying the universe. You assume the role of either the hero god or the evil god and your journey stays much the same, but with you doing different things throughout the levels depending on whether you're the hero or villain, of course. During the course of the story you will encounter various bizarre friends and foes, navigate your way through giant metal death machines in space, and blow up more planets than you can shake a stick at.
I also have the backstory for a sequel to this (Godworld II) in development, but NOTHING done ZDoom-wise yet. :/
Doom Heroes - The levels for this project would be EPIC, far beyond my mapping ability, anyway (I'm talking like 2x eternall.wad, but the maps wouldn't last quite as long as they'd be very fast-paced). They would be immense, very linear and stacked with interactive objects. You would have a boss map after every regular map, as well. Also, throughout the maps there would be "switch points" where you could exchange playerclasses for the main three Doom heroes from Q3A - Doom, Crash and Phobos, and they would have different strengths, speeds, jump heights and weapon sets. Of course, this can't be done on the fly in ZDoom right now, hence why I can't produce it...that and my maps take about half a year to complete even if they're very small Skulltag invasion maps.

So this is one of those over-ambitious projects that would never get off the ground, or if it did, would get cancelled after the third year of development and still only be a 5% total completion.

I'm gathering resources like music (some of my own), monsters and scripts for this project, but I can't see it happening very soon at all. :/ And "Doom Heroes"
is a play on "Sonic Heroes" due to the gameplay similarities, yes.
QuizDoom - Again, more linear levels with dramatic gameplay changes - answer questions with an ACS-based interface to progress further through the levels, with the occasional monster to shoot. There would be varying stages of difficulty, with practically impossible-to-answer questions being asked at the highest difficulty setting. At the moment, I am unable to code a Q/A interface that
isn't buggy as all holy hell, which is why this project is on the back backburner right now.
Insan!ty - The weapons and monster in this project would come from my...er..."collection" of additions to Doom that is Insanity Doom. I'm planning on having maps that progress into each other, with some voice acting from the player character, and some kind of ACS-based story log that allows you to pick up information about the alien infestation along the way. Some of the additional monsters in this mod would have personalities of their own, and boss fights at the end of each level, including any of the modified versions of the Doom monsters I've included in Insanity Doom.
DoomCraft - An RTS similar in gameplay to either Dungeon Keeper or StarCraft, in ZDoom, created entirely by ACS. It's nothing else.
Realms of Zoon - This would be a TC. It's situated in the "Realms" (surprise, surprise!) that Zoon, the supreme entity of the game, is taking over with his legions of chaos. His dark realms are trying to take over the light realms, and you have to save the light ones for some reason. Yeah, another one that really hasn't had anything done to it at all.
