Legendre, I've been following the Unity community with interest and I'd love to build a basic demo and go from there but again its a matter of a dedicated team. I get the impression that achieving that team is really where my focus should be at this point. Does it make sense to put up an advert for a programmer here? Are these designs worth starting a Kickstarter account and offer pay?
I am not exactly sure how you intend to form a team, so please forgive me if I make any wrong assumptions. Also, take my "advice" with a grain of salt because they are solely based on personal experience running my own projects. In my humble opinion, I think there are two big issues:
1) Is this project too ambitious?
(3rd person) Shooter = networking and latency issues. 3D Engine = probably the toughest medium for game development. MMO = the more concurrent players you have, the more difficult it is to make.
Shooter + 3D Engine + MMO + all the features in your description = Probably way too hard for indie. (don't think there are many unfunded indie 3D MMO shooters)
Perhaps you can try to greatly scale down your vision to the point where it is realistic for a 1-2 man team to make in 2-3 months. Releasing a scaled down version has several benefits: It shows people that you are serious, and can lead a project from start to end. It shows people how fun the core mechanics are: lots of designers out there claiming that their design is fun, but you can actually demonstrate yours. It gives you a starting foundation to build the rest of your game, perhaps even winning you some fans or funding.
2) Are you trying to form a team of unpaid volunteers?
I have seen this happen over and over again: a team of volunteers get together to make a game ( e.g. fan remakes of old abandonware), after a few months, people get too busy with real life and starts leaving. Then, the project gets abandoned.
Unless you can continue coding by yourself after everyone left, you might end up constantly putting your project on hold indefinitely while you look for the next volunteer team.
Have you thought about making it a top down shooter in Adobe Flash? Flash actionscript is super easy to learn and work with, I think you should be able to come out with a small singleplayer version of your game to upload to a flash portal within weeks, given that you can produce your own artwork. If the game gets popular, you'll start to attract other developers and fans etc.
An indie game that started like this is "Dead Frontier". The developer uploaded a 2D singleplayer demo version on Newgrounds, then made a 2D multiplayer version on his website. One year later, it has evolved into a profitable 3D top down shooter.