We're not going to retire out the older ones. It wouldn't be fair to those still working on achievements or who join up later or decide to collect them later. I don't really like the idea of weighing them, either.

and I have talked about a few ideas before, like trading in 5 to get another chance at one or bribing Raffles with a chance to get a specific species (so you have a limited pool to pull from). These wouldn't be unlimited like you couldn't bribe Raffle a bunch each day. These are just a few things we've discussed (that a few other users have brought up too). SO WHO KNOWS WHAT WILL HAPPEN ;)