I also think a massive cooldown would work great to balance it! Not a fan of the “only change them one more time and then never again” because tastes change over time. What a user likes for their progens one year may change by the next.
The fact we even get as much customization for our progens on this site is incredible because on FR, not only are you limited to the color wheel pre-expansion, but you only got to pick two colors, and the third was randomized, and then your second progen was completely randomized. So I think being able to re-customize our wolf progens would still fit the spirit of this site! Though again, a major cooldown is justifiable, but I think it would be extremely worth it to exist <3