Hm. I have a few basic ideas, nothing fleshed out yet.
First of all, I'd like to bring up my idea for a TF2 RTD.
The TF2 one would involve me having to communicate separately with the two separate teams. Maybe getting a top-down view of the map, and having that to keep track of where everyone is. Classes would get bonuses, can select their loadouts, and, as the game progresses, people can A) Buy weapons, B) Trade weapons with another player, even from the other team, or C) Just wait until they FIND weapons. I'll show each player what hats they have on, what loadouts they have, and any effects they have. This information would be shown to everyone but the other team. Once the round starts, I'll give the RED team a turn or two to get into their positions and BLU just goes for it. Points are earned for kills, objectives, and overall winning. These points will replace real money in the purchasing of Hats, Accessories, and Weapons.
I feel that it could work with a little effort, this could come to life quite well. Source Filmmaker can be used to create any class loadout, which can help add to the game feel, and overhead maps are easily found
here.As for other ideas...
1. An RTD based off the concepts of Soul Eater, players can choose to be a Meister or Weapon, each wither their own perks. Meisters can choose whether they want a player to be their weapon, or an NPC, and a select few Weapons can choose to not have to have a Meister. The ultimate goal of the game is to go on missions and gain Souls, ultimately gaining enough for the weapon of the team to become a 'Death Scythe', an incredible powerful weapon used by Death himself. It could either have an Off-Duty thread, similar to ER's, or just have a policy that players must be on missions at all times, unless doing something important otherwise.
2. An RTD where players play aspiring surgeons, bumbling their way through medical school and ultimately stumbling into a job at a hospital. Taking cues from Surgeon Simulator, but focusing more on the 'Dear god why are you so inept' reasoning than the 'Whoops, just slit the patient's jugular, I'm SO clumsy sometimes!'. Rolling would be mostly towards how much you fucked it up, ranging from 'Wow, he's actually done it!' to 'Well, he's dead. NEXT!'. Real-life surgery situations will be faced, blood will be shed, goofy grins will be formed, and hilarity shall ensue.
3. Assassins! There are three ways you could take this. The first one, taking on a more Brotherhood-esque feel than any of the others, would feature players as Trainee Assassins, taking on assignments as they work their way up the ranks to take on incredibly important assassinations! Secondly, Having a more 'Hitman' kind of vibe, but still following the same principals.
Finally, there's an idea of time-travelling assassins, sent out to prevent or cause some of history's most famous assassinations. And of a few of the not-so famous ones. And, following the 'Hitman' logic, nothing will be as easy as it sounds. If you need to prevent Lincoln's assassination, you need to make your way inside the theatre with or without your weapons of choice, you need to find your target, John Wilkes Booth, and you need to dispose of him without anyone knowing. Or, at the very least, without anyone knowing that it was an assassination. Once that's done with, you need to make it back to your designated zone of pickup.
Some missions will require multiple people and teamwork, but when those aren't happening, people will be spread out across time and space doing their own things.
Would anyone be interested in hearing more about any of those?