Natural Talent's problem
Lack of initial stats, and lackluster overall. As it is, it's not even worth it on hybrid champions. It seems that the 3% spellvamp is supposed to be more relevant early game and Natural Talent for lategame, but thats not the case, NT is irrelevant all game long while the spellvamp gives a bit of early sustain and scales with your damage later on.
Ideas:
1- 3 AD at lvl 1 + 0.7 per level = 15 AD at lvl 18 5 AP at lvl 1 + 1.18 per level = 25 AP at lvl 18
2- divide it into 2 different masteries