"We're killing spellvamp".
K, so I find there're likely two possibilities for this decision.
A, You've tried spellvamp ratios and they.... Somehow, I can't actually even fathom how.... Didn't work. In which case, pray tell. What didn't work about it?
Or B, You didn't even try it. Despite it being a simple and neigh guaranteed to work solution.
Jus' want some answers. http://boards.na.leagueoflegends.com/en/c/gameplay-balance/rTxR5mVM-i-just-realized-a-mage-gameplay-update-is-the-perfect-time-for-spellvamp-ratios