Ive always wanted to see an exchange for games like this(random pulls) . example being youve got five legendary champs(fully ascend and max lvl) you don't use or want you could exchange them and silver(or gems) for one you do want or at least a faction you want
They'll never do this. Anything that allows you a guaranteed way of getting a champ would completely destroy their business model.
What they have hinted at doing is a system that lets you recycle duplicate legendaries, but they haven't really expanded much on the idea. I expect it will be something allowing you to convert them back into sacred shards for another roll - perhaps something like 2-3 legendaries for one sacred shard.
Hell id be ok with that too especially if it was for more then dublicates
