Some may argue that because there was nothing given for excess shards before, there doesn't need to be a decent exchange system in place for them. I would say, however, that this is not the case.
We have just seen the release of a new chromium character (Rex), and eventually we will see the introduction of more. The problem is, for people who already have all, or most, of the characters already, it's somewhat silly to buy more packs in hopes of unlocking the new toon/toons. You could spend hundreds of dollars on packs without seeing him, and currently, anything that is non-Rex is useless (due to the horrible rate and design of the shard shop). What this means, is that to a high spending whale, the value of a pack is close to $0... you reasonably aren't going to get anything.
For people to continue to spend money on packs, they need to actually be worth something, and with the current system, the more you spend the less valuable the packs become. I imagine this is not the way that EA want their game to work, they should want to encourage the people who are willing and able to spend money, to spend even more.
Offering more comprehensive rewards for excess shards would increase the value of packs, and encourage people to continue to buy them.