If anything there should prob be more uses for coins. As of now most the people still playing the game are only using rubies to get specific pieces rather then using the coins to get the packs (thereby completely ruining the exchange rate) maybe there should be more packs of some kind that would encourage people to buy them instead, or maybe some kind of faction pack.
All the coins I had the other day I just ended up converting to 400 or so rubies in order to buy 2 gluttonies lol. I don't think this would be considered exactly optimal.