Blue "buff" nerfed?

So I saw a youtuber say that Riot is nerfing the blue buff taking away the 15% AP bonus from it just to make the blue buff last 2 minutes longer, that's great for every midlaner mage that uses Mana but what about the mages that don't use mana? What's the point of ANY buff at all? I main Vladimir and the 15% extra AP helped a lot specially late game, but now any energy based mage is just screwed by this because a mage you COULD use red buff... but lets face it that'd be a huge waste on a mage that doesn't generally use auto attacks, RIP Not only is Rylai's being nerfed to make it harder to stick to people it also has less health and AP, it seems Riot's idea to rework and buff assassins is to nerf everything else to make them look strong xD