If you have a goal like that, I'm afraid there's really no other way but to really show off all of the features working in a basic way in the game. It doesn't need to be too polished, but without a vertical slice it's hard to generate that kind of funding.

Can you tell us more about the features you want to implement? Maybe there's a simpler version you can hammer out more quickly, and then build them out more robustly once you get funding.

Can you tell us more about the features you want to implement? Maybe there's a simpler version you can hammer out more quickly, and then build them out more robustly once you get funding.

Quoting the campaign description:

The idea
WoC will be an open world sandbox game, including the following features:

An endless world with different biomes including plains, forests, mountains, deserts, coral reefs etc. and large caverns
Building everything you can imagine (see below)
Singleplayer and Multiplayer (in LAN or online, see below)
Mod API for client and server (see below)
6 races in 2 factions: The Baldori alliance (Humans, Dwarfs, Elves) and the Somera dominion (Orcs, Trolls, Undeads)
Crafting with different professions like blacksmith, forester, alchimist, enchanter, tailor etc. (You will be able to learn 2 of these professions and craft some of the items of other professions without learning them.)
Quests and leveling
Player versus Player (PvP)
Dungeons and raids
...

But the most important feature that offset this game against other games is:

Building
In WoC you can build everything you could imagine in creative or standard mode. In creative mode you have unlimited resources, but in standard mode you have to cut trees to get wood, gather ores to craft iron axes, diamond pickaxes etc. Yes, I know that this sounds like Minecraft, but it isn't. In WoC you are not limited by blocks or voxels but can place everything whereever you want. [...]

About Multiplayer features
This game could be played in singleplayer and multiplayer mode. In multiplayer you have standard features like chat, parties, guilds etc.

If you want to play together with others, you can play on your own server or in LAN. But you can also connect to the official game servers or to third-party servers. You will have to pay a fee if you want to play on official servers (there are 60 days free gametime included in Digital Edition and 1 year included in Collectors Edition). Some third-party servers may be accessable for free while others are subscription-based. This is because the physical servers are not for free (hardware, traffic, maintainance, etc.) and I don't want to develop a game with free server access to sell you healing potions for $1 each (others would call this "free to play", don't know why). But unlike other games like World of Warcraft you will be able to play the game even if you don't pay the monthly fee.

About the Mod API
The Mod API should allow players which are familiar with coding to add NPCs, quests, items or whole dungeons and biomes to the game. Not all of these features may be available at release because the other features of the game have a higher priority and there are limited resources.

You won't be able to get 1,000,000 € with this concept, even on Kickstarter (even with a demo), you'd almost need a full game for that kind of cash, or a very good track record. The problem is the technology issues with scaling this kind of thing up, and because it's using essentially novel/untested technology. Backers are skeptical (as they should be of anything very new).

You might be able to get 200,000 €

I recommend you scale back your initial release, and plan according to that budget. Remember, you can always add more later once the game is done and starts making profit, or even as stretch goals.

Also, put this on Kickstarter. Indiegogo isn't very good for games. Find a friend in the UK to help you. It's worth the trouble.

Some more details/suggestions:

About the Mod API

Most backers are not modders. Almost nobody cares about this who will be backing your game. I suggest you not spend time on this, or demonstrating it. Focus on other areas, and reduce your funding goal accordingly to cover only the things that will get you backers. You can always add this in later on.

About Multiplayer features
That sounds fine. You can't really demo it, but players may like the concept. This will be one of their leaps of faith, but since most backers won't understand the complexity here, you should be pretty safe as long as you're solid on everything else.

Building

Focus on this, and pretty much just this. You need a serious technology demo to prove how this works. This will be the key to getting any real backing.

The idea
An endless world with different biomes: OK, yeah, that's fine. Make sure to include some really good concept art, and flesh out at least one environment for your demo. It wouldn't hurt to have some more unique areas too, though.
6 races in 2 factions: People are really starting to get over the canned fantasy stuff. Please drop this, and come up with some original races: That's what will win you buzz and backers. If you need to, hire artists, writers, and designers to come up with this, and include some serious concept art introducing people to these new races.

Let me know if you need help with anything, or more specific suggestions/references.

Good luck, the building stuff sounds interesting, I'll be excited to see how it works!

Does anyone know how to find some people who join my one man team even if I can't give them money?

You can post here: http://www.gamedev.net/classifieds/category/5-hobbyist-projects/

But, if you can't give them money, it's nearly impossible. You'd honestly be better off joining a team which is doing something similar that you could contribute to.

I will try to implement the FBX model import next and then I try to implement the building system. It's too much math, but I hope I find out how this could work. I actually liked math in school, but now it's too complicated to like it xD

If this and some other features of the game are implemented, I will publish my Indiegogo campaign. But it would be more successful if I am not alone...

If you're struggling with that, then the building system you describe may be a bit out of your league right now. I can not adequately put into words how monumental that technology would be. Placing and tracking billions of small items is much more complicated than placing a few items on a map and repeating the process; it requires a very sophisticated data structure, and rendering pipeline, along with a UI that makes it manageable for players.

What you're talking about is technologically comparable to the early claims by Euclideon for their 'Unlimited detail' voxel terrain, which were met by harsh skepticism... and several years and several million dollars later, they've scaled back their ambitions to simple architectural visualization software.

http://en.wikipedia.org/wiki/Euclideon

Real building games use large voxels "bloxels" for a good reason; the alternative is technologically impossible without some kind of revolutionary new methods - methods only likely to come from mathematical genius of the Nobel-prize order of magnitude.

Sounds a little like http://stonequest.de/

Maybe you can team up with him. The dev is from Germany as well ;)

(See also http://zfx.info/viewtopic.php?f=10&t=3352&start=90 for more (technical) Information)

The idea
WoC will be an open world sandbox game, including the following features:

You most likely won't be able to raise a lot of money based off an idea alone. Let face it, most people can come up with ideas on paper. Maybe during the beginning of Kickstarter you would be, however due to a lot of recent projects promising loads of features have failed living up to the ideas and promises, people have become a lot more sceptical towards backing.

We have even experienced highly professional developers raising a lot of money on kickstarter, but even they have failed to deliver. Somehow, the kickstarters sound a lot better on paper, but are extremely difficult to execute. Beware of what you promise your game will be. The more you promise, the harder it will be to create.

If you are a small indie with limited experience, I would suggest not going for a kickstarter or indiegogo until you have a working demo, which has been tested. I also would not raise more than you realistically could get. It is better to aim for less, and hope for more. (So you aim for 10.000 but get 25.000)

Smaller projects are a lot easier to pull off, and you will be in a lot less trouble if it goes wrong.