Buffing Mirror Shell is a poor answer to the current MR starvation
On PBE: Mirror Shell (R3) MR increased from 5 to 6
For the purpose of mitigating bad matchups or magic dmg lane bullies and things of that nature, the runes system is very unwieldy because you have to switch one of your trees over to Resolve to get either Armor or MR. This is not feasible in most cases because the secondary page offers important synergies depending on your strategy, it's not like you can just dump it to get some MR or Armor.
In the old system it worked because you could just switch out a few of any type of rune without totally altering your entire strategy. Even marks offered a serviceable amount of armor or MR if you really couldn't afford to switch the other types.
To deal with level 1 stat flexibility issues in general, we need a flexible system. I've said it before and I'll say it again. Level 1 itemization should have this role. We need an overhaul so we have more options for our starting items to adapt to lane matchups.
