Was the Lissandra nerf really necessary?

It seems silly to think that nerfing her damage is an all-fixing solution. It's an 85 mana cost ability on a champ that already has terrible base mana regen. But evidently enough people got butthurt that this became a thing. It has a low cooldown to tempt people to spam it. It's not like Cassy's E where she can just shred people with it. Are we going to nerf Cassy, too? OH WAIT... Nerfing damage by 25 points is silly. If you're doing to do that, then reduce the mana cost by 15. Seriously, it's a medium range skillshot that needs to be aimed through minions, already taking Lissandra away from her safe distance. It's just sad to see a champion that they were previously thinking about buffing is getting a nerf because enough people got butthurt about the cc.

In the end, 25 damage is only 25 damage. But I do think that there should be a compensation buff in the cost of the ability.