Well i dont see it like that,if you are willing to donate to the server to keep it running and for fresh content to be released you should get some perks.
same thing with real life,you know money usually buys things,dont see why a person who has invested in the game shouldnt get some perks,not asking for anything that affects gameplay like OP gear or whatnot but a forum title,ingame title,etc,etc,things like this will make people want to donate which will result in a better game.
personally i still havent spent a dime on the game because im waiting to see how it turns out,but once we get the definiteve version running and if it all goes smooth i will be spending some money in the game,its a normal thing for donors to get certain ''perks'' for helping to keep the game running...
and to add to the subject you seem to forget that one of the main forces that drives people in mmorpgs is bragging rights,this applies for mounts,titles,gear,pvp kills,raid bosses killed,etc,etc...without that players wouldnt have a reason to play the game...