I ask this, because AD is clearly the higher damage type, and offers far more penetration options than AP, not to mention base MR is, more often than not, low than base Armor, only to scale higher than the base MR by the late game.
It just seems weird that you'd be offered less of the resistance for the type of damage which is higher in the early game, when runes are most important.
Unless there is some mathematical reason behind it that i'm not seeing.
Kirius Dark3 votesArmor value is always worth more especially early game since it reduces damage from every champ's autos, minion aggro and jungle monsters. Armor prevents from more damage sources
Illâoi Evê Siôn1 votesThey used to be equal. Then Riot gave every champion +3 Armor and reduced their value to 1 per Seal. I think they did it because everyone needed to take Armor seals in order to be effective and they wanted to give players more of a choice.
deadlychuck1 votesBut even in the case that they were equal, AD and AP damage output isn't anywhere near equal.
oSEXYPLATYPUSo1 votescuz champs (all but thresh ) get armor per lvl through out the game.
and all champs naturally get ad per lvl
ranged champs have a flat 30 mr and stays that way. most melee champs get mr per lvl and tops at 55 by lvl 18
Hauling Ashe1 votesTake a look at the stats for MR items.
for example. You get 60 armor but only 45 MR out of that.
only gives you 55 MR compared to 
100 armor.