User blog comment:Krufix/Armor/Magic pen is anti health stacking./@comment-9369480-20130723162841

If a Singed is building glass cannon + Rylai's, he should uninstall. A good Singed has 140+ of each resistance, around 2k mana, and around 4.5k health.

Now that that is out of the way, this is a good read as it shows why building resistances and penetration should come back, instead of just the health stacking meta.