Syndra's ult should work like Shinbi's from Paragon
For those who don't know, Shinbi's ult, ALL-KILL, relies on a stacking system. For each ability she lands, her ult does more damage up to 8 stacks. Syndra's ult should work the same way in that her ult does more damage when she land's her abilities. This gives her more of an incentive to first of all LAND her abilities and use her ultimate as an execution instead of a one person instant kill.