I don't understand why Vayne is considered a tank buster when ADCs already inherently counter tanks
%health damage is one thing, but every ADC already specializes in hyperscaling sustained damage that far outpaces any defensive stats. Maybe ADC itemization as a whole should be weakened, with sweeping buffs across the board for their actual kits, so they're picked more often for their individual strengths. This will actually make Vayne picked for her tank-busting qualities. All the ADCs would have their kits buffed
Except for
and 
Not a suggestion, just a thought. (And I'm not talking about increasing their base damages or anything. The whole of their strength numbers wise should come from items. I'm talking about making their kits more geared towards their strengths)
she got an indirect buff, as she is one of the few adcs not crit reliant.