OK then, my view of how shootmania would work.
- Building
The building part of shootmania can be divided into two parts, one part for building the map, the other for the blocks.
-- Map
The map building is rather straight forward, its just like in trackmania, placing blocks in a grid.
But the ground can be modified, like the way you create mountains in
RCT3.
That way you can also color the ground with different textures.
Also you have a selection of trees that can be placed anywhere independent from the grid.
You have a basic selection of blocks when you first start playing.
-- Blocks
This is what i have been thinking of a pretty long time, but i came up with a solution.
When building blocks you start with a 1x1 grid in which you can build a block, this grid can be resized anyway you want.
Then you can start making structures.
I was thinking of some sort of the sims way of building, making walls and giving them a texture, then placing doors and such.
Then for the furniture, you start with a small selection of furniture(ish) parts, like barrels and planks of wood, also a TMUF car

.
You can place these anyway you want to, and we're going to do that with a Drag&Tilt tool.
This tool consist of drag arrows (arrows that point to X,Y,Z,-X,-Y and -Z) ones you click and hold those arrows, you can drag the furniture in that direction.
Then the Tilt tool is something like this:

The red part is the furniture, the yellow parts show the ways you can tilt it, and the black things are the handles.
With a tool like this you can move it in any way you want and place it anywhere you want.
Now i said you start with a small selection of furniture, indeed, cause we are going to use maniaplanet to buy them with our planets we earned while fighting.
Nadeo creates all these furniture things and makes new ones all the time.
Also with our planets we can buy textures for our walls, and for our character and guns.
Therefor we can also sell textures for characters and guns. (walls i don't know if its possible)
Also blocks in their entirety can be sold/bought.
Also players can add triggers for any maniascripts they want to add, this is the same for the map.
Ok, having this part done we're moving on to our character.
- Character
Our character, or avatar as i would like to call it, is the most important thing of shootmania.
People recognize you by it, and its a way to show off your virtual wealth.
Because, we can dress our avatars any way we want!
Nadeo makes all the clothing for them (the models), including hats, boots or even glasses, which we can buy.
Then people can retexture all those items, and again sell their textures on maniaplanet.
Also loads of facial features can be created using (again lolz) a sims like character editor, giving us the opportunity to really create anyone we want.
Hair can also be uploaded over time by Nadeo, but we can color it ourselves, we don't need hair textures...
Also we have the ability to choose if we want a male or a female avatar, but that's too odd.
But with all these people having different looks, isn't it real hard to keep team mates from enemies?
No, red team walks on a red shadow thing, and blue team on a blue shadow thing.
Also when we aim at people we can instantly see if they're red or blue team.
And people that don't like this can always create special avatars for their maps, so everyone on the same team looks the same, or they can choose to give all red players a red hat, and the blue players a blue hat, whatever they want.
BUT the creator of the map must have these pieces of clothing bought/unlocked, cause you can't just give all teams a 2 million planets hat while you're a poor guy that's only walking around in a paper bag.
Now over to the gameplay
- Gameplay
Different modes can be played, or even created using maniascripts, its up to the builder to explain these different modes.
You spawn in a spawnblock at the beginning of a match with the guns you chose for your character.
Player can not collide with each other just like in trackmania.
Players can carry 3 weapons they pick themselves, one primary and two secondary.
Also they have to ability to call in an air strike after a preset number of kills, this is option though, and up to the creator whether to put in or not.
Players aim with their mouse and walk with wasd, they shoot with the left mouse button and shoot secondary weapons with right mouse button.
Players can use the scroll thing on their mouse to switch between secondary weapon one and two.
When a player has a flag he/she can not use their secondary weapon.
When players are out of ammo they can go to a reload station, which are mostly near the spawn.
To win planets players must kill a player, easy.
When the players team wins he/she gets a preset amount of planets, this preset is up to Nadeo, to prevent milkers.
Also players can enter tournaments in which they can win more planets than in normal matches.
People can put bounties on other players heads, and the player who kills the wanted player gets the amount the bounty was.
Now, this was rather simple, now to the last part, weapons.
- Weapons
Weapons are very important, they can make the difference of somebody ragequitting and smashing in their pc or having that same person host a massive party.
Nadeo has a selection of weapons made when they launch the game, but make more time after time.
People start with a basic rifle and grenades.
People can buy weapons on maniaplanet only from Nadeo, but retextures from all players.
A rocket launcher costs more than a simple six shooter, but that is plain logic.
People can buy upgrades to improve reload speed, damage, ammo slots and accuracy.
The builders of maps can also choose to give players weapons they want, just like the team clothing.
Again, the builder must have these weapons himself.
Where you can change your avatar you can also pick primary and two secondary weapons.
Well, i guess that's about it then, tell me if i missed something.