Lost Mastery Exp
I like this idea a lot.
Anet, make it happen!
Would be nice to have considering both PvP and WvW offer repeatable reward tracks. Then again the argument can be made that they get reward tracks because that’s the only way to obtain the same amount of rewards in those game modes as you could earn by playing PvE.
I just wouldn’t want it to be a mastery line so much as a whole reward track system where you can pick which one you want to do when, but only if you can’t unlock another mastery line to work on (eg if you have finished all of them or don’t currently have enough mastery points to master the current one you are training and start training a new track)