As far as I know the only effect of the father winter trait is to boost aspiration points from completing whims. But whims have been replaced by wants so I don't know if the father winter trait was updated for that. A mod to change the trait and make it more useful sounds interesting.
You can have sims with multiple hereditary traits (traits that can be inherited). I have had sims with the combination of the spellcaster blood line trait and the sulani mana trait and sims with the light house trait and the spellcaster bloodline. I haven't tried this with the father winter trait yet.
Here you can find an article about combining a few traits with the father winter trait. Werewolves wasn't released at the time of the article but if it can be combined with the spellcaster bloodline trait, I suppose the same can be said for the dormant werewolf trait.
I like the idea of combining the father winter trait with cold acclimation reward trait. It does seem fitting.
By the way, this can be done with cheat codes as well. You don't need a mod to allow more traits to add a hereditary trait. But the mod might make it easier to add them. Traits your sims can inherit, unlock or buy with aspiration points don't count towards the limit of traits in CAS.