So where will the middle ground be with ADCs?

Because if armor penetration and the items are too weak these abusive ADCs will never build it, thus they lose out on that stupidly good early game powerspike from building these items. Then they go back to the crit builds where they're stuck being somewhat useless until mid-lategame when they get core items and hopefully do something before getting one shot. And even then you get abuse cases like Caitlyn being the best and most likely to survive in these scenarios.