this is just a few things i've seen in other WCS servers up now that we might consider adding to ours once it's up agian:

Race of the Day - each day a random race is picked for each player from the races they have available. when playing that race they gain extra xp. this would encourage people to always play different races and mix things up.

Assists - gives xp for damaging an enemy that is killed by a teammate (CoD style) doesn't have to be alot, just encourages teamwork and killstealing isn't AS bad.

Starting Levels - each player should get free levels upon joining the server that they can apply to any race they want. this doesn't do much for existing players but it gives new people a little boost so they're not starting with nothing. Even if it was as low as 5 lvls, just so they can have a few abilities to start with.