LeBlanc can get kills, but she has trouble doing much outside of that. She can't even push minions, which is pretty sad considering she's AP. The jukes you can pull off with her are pretty fun though.
Originally Posted by konfetarius
The perpetuation of this hilarious myth is the greatest buff AP ever got in Dominion.
Yeah, magic resistance easily shuts down a wide range of AP champions. The changes to penetrations only help if you actually get a Void Staff, which isn't necessarily easy to accomplish in a game that ends a little after you get 2 major items - especially with Wogglets and/or Blackfire being pretty solid first-buys depending on the champion. Not to mention the unique passive/active on a magic resistance items tend to actually be useful against any source of magic damage. It's not an equivalent to armor and in nowhere near as bad a spot as armor at the moment.
The hard-counter to flat penetrations is resistances. If you have 50 MR, an opponent with 50 magic penetration is going to deal an extra 50% damage against you. If you have 200 MR, an opponent with 50 magic penetration is going to deal 20% more damage. Considering things like AP, AD, and CDR increase your DPS by the same percentage regardless of resistances, that's a prettttty favorable match-up for actually grabbing magic resistance.