Viktor is probably one of the worst choices if you want to play a mage as a support. 3 of his skills do nothing but deal damage so he's extremely AP dependent. How do you farm 3k gold to upgrade your hex core? And most importantly he's very short range, has no poke and no engage.
I don't think it will work well, as victory don't have much high base damage and his abilities has long cooldowns. Victor need high cost ap items to be good at his job and this is not the case, in addition it hard to make his stun work maybe with ashe it will work.
If you want to play mages as supports I'd play champions with CC and hard engage. For example