User blog comment:Lukeatlook/Pyro's Item Overhaul 11 - The Mage Project/@comment-1330314-20150110223619/@comment-1330314-20150111000414

"That's what mana is: a resource. In a very simplified way it comes down to a binary dilemma: do you have enough mana to cast spells or not? Same as with health - you're alive or dead."

The problem with mana is that it's the only resource that's generally not fun: health has tons of ways of being interesting (if only because it's the stat that literally keeps you alive), energy gates spells much more visibly in combat while being fun to spend/gain, and custom resources like heat/ferocity/fury are all tailored to their champions in such a way that they carry unique gameplay of their own. None of these are seen as boring or excessively limiting, so there's no desire to "solve" these resources by lessening their restrictions through items. Even mana regen is fun to build, because it lets you cast spells more freely, but mana itself doesn't really enhance your playstyle or your champion in a manner that's truly appreciable (unless your kit scales directly with mana). Giving mages greater access to it (but then again, why?) doesn't solve its problem, and may make it even more difficult to address later on.

I also disagree that lack of penetration would make tanks and bruisers impossible to kill. Tankiness is a reaction to damage: if damage-dealers cannot handle tanky champions without a counter to that counter, then either tanky itemization is too strong or damage itemization is too weak, and I think neither are true now. In fact, bruisers right now have been at their weakest since the start of the game, as they can now die extremely quickly even with a full tank build.

Put another way, tanks and bruisers are meant to survive a certain amount of time in fights. If they survive for too long, then they could be made to be less survivable through nerfs to their tankiness, and if everyone takes too long to die then buffing damage items would solve that too. There is no need for second-degree counters, just as it would be a bad idea to have a stat or effect that reduced resistance penetration/reduction.