So I saved up for my first discount gold pack, and I unlocked Beyond Batman! His ability is even different from the normal, Future Batsuit : Prevents stunning. So I guess he is not as good as the normal batman since that passive damage boost is just awesome.
So if you want any of those special characters like Arkham Harley, Beyond Batman, Prison Superman etc...you'll have to get them from booster packs
Same here I just bought my first gold booster pack and it gave me Superman Prison? His ability is super health "once per match, when Superman is at 40% health or less, he regenerates health for 6 seconds."