It's possible to do anything, spec into Magika and become a Werewolf.
Viability for the type of content you want to do with it is another question.
PvP? VMA? Trials? Or just general running around PvE are very different things.
Generally speaking Magika is more naturally aligned with Vamp. WW with Stam.
Magicka werewolf just doesn't mesh right. All of your damage comes from Max stam and max stamina. The only thing that uses magic is the heal and it heals off of max health now.