User blog comment:ClariS/Escalating Return: Damage Reduction/@comment-4929329-20120816063754/@comment-81.200.170.248-20120816131358

I was under the impression riot had already normalized all damage mitigation skills so that true damage is unaffected. What skills actually do mitigate true damage atm? Also things which INCREASES damage works just fine with true damage (Vlad ult, Kayle Q, 21 point offense, etc).

Also your second point is plain wrong. %-age mitigation amplifes EFFECTIVE HEALTH (and healing/lifesteal), buying hp is in no way more efficient than buying tankiness in general. Actually, in the specific case of Garen the passive part of his new W makes armor/mr cheaper meaning it more effecient to go heavy on that side rather than on hp.