For really high level wizards, there could be a certain thing that allows you to equip multiple pets at once. This way you could specialise multiple pet for multiple talents. As these leashes give such an advantage, they should be very expensive (if they would cost gold). - Adrian Hawktalon
It's way too overpowered I agree, but it could be workable in PvE if double talents don't overlap. So having 2x +15 resist pets would only give +15, not +30, but would allow additional talents.