If you are planning on staying around and putting all the effort you say you are, you can expect a LOT more then 10-15. Good servers that stay around get a huge following. Guild Wars was hitting 120+ on at one time when i first came here, Krushers was hitting 80+ Winters Roar and Raid Addicts were hitting 40-50+. Once again these arent the totly player base just what was one at one time.

I am not trying to discorage you just letting you know that If you build it they will come expecialy since the player base is a lot bigger now then it was a couple months ago when 4.4 was going strong.