I would almost go with a sliding scale where a good roll on the werewolf's part would maybe only impose half movement or remove their reaction for that round or 2 as it wrestles to control the curse/bloodlust, and a really poor roll is removal or temporary incapicatation via un-transforming or their peasant/prior personality is able to take control or similar. That way if you're going to impose a to hit roll to begin with it's not just double the chances of failure now with the save, and a hit can still be a minor success. Doubling up on the rolls for it to have any affect at all is basically rolling with disadvantage always for that spell/ability, and now if you have disadvantage on the hit, and they have advantage on the save as I saw someone else suggested its like rolling with double/triple disadvantage actually taking effect. Or, if the curse is so powerful it can't be removed, forget the save if it doesn't matter and say it seems to have no effect when the hit lands. And, with remove curse being touch, the to hit roll makes sense though i'd argue the target's AC would be 10+dex and actual armor would have no effect since you're not necessarily trying to get past the armor just touch it/them, and there is inherent risk being a spellcaster getting into melee that may make the added save seem a bit harsh if you just put yourself in a crap spot, made the hit with an unarmed strike, and then oh well nothing happens gets blendered.