I think the really need a system for that, because most players are stuck on developing because they have only limited opportunitues to reach dinos. Myself playing from the first day but i fidnt even see the 70% of dinos, maybe because im from a smaller country. On the other hand, i got thousands of unused dna, because i dont want to evolve useless dinos, and dont have money to further evolve others.
My idea is. That you can change unused dna for othets you need for a rate, or money. Lets say 5 dna for 1 other common, 50 for a rare and 150 for an epic.
Or simple sell it for money.
That way you can slowly evolve dinos, that arent in your area, or finance evolving others