I disagree, as easy as deck building already is in this game
Getting a random nymph and building a specfic deck for it makes me mroe fun then changing it and then build boring decks with it.
Besides people who got 6 nymphs will make them all into the same color, and the totally bully the ones with 1 nymphs
Imagine 6 nymph black-holing you!!!! for example
On another thread I think someone suggested only allowing you to switch it to a type of nymph that you dont already have. so the only way to have 2 of one type of nymph is by getting one from the oracle. (change one then win another of the same type from oracle)