If overall DR% and AP% was soft-capped at 30% or 40% and gave diminishing returns beyond that point, it'd fix both DR% stacking and AP% stacking.
It'd also help if any source of AP% and DR% outside of auras and duration-based buffs were lowered across the board.
It'd also help if any source of AP% and DR% outside of auras and duration-based buffs were lowered across the board.