So it seems i could be wrong i thought tht data sense will always be carrier controlled but from the wp8.1 leak and the wpcentral team gives 5 o meter to it(rumor)it would really be cool if we could get it :'(
I see no reason why it needs to be carrier controlled, as far as I know it just compresses data... Opera browser does this without carriers being involved so why can't MS?
Carriers are even less likely to push for it because if you're using less data they're making less money, you're more likely to lower your plan or not go over and incur extra charges.