They need to nerf it, and not buff other atk oriented masteries. See how it goes. If some still are weak, then buff em.
As it is now, TLD is the real issue on several champs. I feel TLD makes Ahri super strong even when you miss E, your W helps proc it, so it helps get kills. If anything, TLD needs the nerf, not Ahri's charm.
Shoot, even take off the MS temporary increase that comes with shooting Q, maybe make it only give buff for landing it, or just not have it at all (like S4).
AND, Riot needs to go after the real problem, making better masteries. Since the masteries for mages are only 2, 3 if you play shield or heal giving supp-ish mages. And Assassins have 2. ADCs have like 4 masteries to choose from, but b/c TLD is OP, they go for it (sometimes Bloodlust). Tanks get their things (or are aholes and go TLD).
So they need to do a better job of making them better, or in my opinion, they need to nerf TLD and make a new mastery that is more relevant.