Hello!
Here is my way how I exploit Arena points to get S3/S2 epix:
You need more accounts, or few friends (3). You make two teams 2v2, one with you and one of your friends, one with two other friends. Then you get to queue with both teams, and just wait and requeue, until both teams have invitation to arena at same time. Now you change turns, once wins your team, once team of your friends. Thanks to getting arena points for loosing too, you (and your friends) will be able to buy epics very fast.
(I searched a much, nuthin', so i hope it is not a repost)