Suggestion: Introduce a New Mobility Rating that Affects Runes

One of the problems with balancing marksman vs melee, tanks vs assassins, etc, is the issue of a rune or item being designed for X class but Y class actually ends up abusing it, forcing Riot to nerf it out of existence.

Right now they have one binary category of range/melee that they can somewhat play with to force items to have different rules. But that's very jaded, and doesn't allow a slider of strength depending on the overall toolkit of a champion.

Instead, I suggest some items/runes include a multiplicative value which depends on the mobility (or some better metric, I'm open to suggestion here) of the champion. This would allow highly immobile champions to get runes which amplify their strengths, without breaking the game.

A current example is Bone Plating. The value scales 20-50 with level. But what if there were a mobility mechanic such that say, Jayce only received 0.5 effectiveness of that rune, while someone like Mordekaiser might get 1.5 times. I'm making these numbers off the top of my head, but I think you get the idea... and I think it would do a lot to give levers of power and balance to the game.