I personally dont like the idea of a new currency but perhaps if we could trade existing shards in for a new one (RNG) of the same teir at about a 5:1 ratio could be good. Just the way it is at the moment I feel it puts a barrier against anyone that doesn't want to spend 20-30 hours in each teir each time they want a new hero. Is shard grinding the end game or is onslaughts?
I haven't been playing DD2 long but already I am feeling frustrated by the low drop rates for some shards. What makes the pain real is getting many many many shards for hero's that I do not own. I've seen a lot of people talking about the issue but nothing that I'd consider a really viable fix. Being able to buy or make shards will simply stop shards being RNG and introduce another (4th?!) currency into the game. Therefore I propose that shards be treated the same way as weapons. Only shards that are useable by characters in your deck can drop. This will remove the pain of seeing literally unusable shards drop and reduce the pool of available shards effectively increasing the drop rate.