As mentioned by others, I find it SO disappointing to have a pet get a totally useless spell (such as Snowborn on a life pet). If you hatch, you have to do another 1,875 points of training, to probably have the same talent manifest. What about treating talents a bit like training points? Make talents so you can buy back a talent slot?
I would NOT like this if it is crowns only, though, because that would massively imbalance haves and have-nots.
In addition to it costing gold (or gold OR crowns), it could cost training experience as well. I suggest that the experience cost be the talent rank x 200. If the talent you want removed is common, you would have up to 200 xp removed from your pet, as well (as few as 125 if your pet is teen). If the talent is epic, your pet would lose up to 1,000 xp.
This feature should NOT apply to non-talent cards - cards given at baby, teen, adult, ancient or epic.