Masteries

I see many posts about people hating that assassins build tank items. Yes this is a bad thing in general, assassins should be glass cannon with mobility to survive, but this stems from another issue I believe.

When the keystone masteries were implemented into the game it generally just increased damage. Even one of the resolve keystones allows for a (although slight) damage increase on a basic attack. Damage was increased without a real increase to tank.

Strength of the ages seems to be the only real solo defense increase keystone and that 300 health is gone real quick in any fight. (While windspeakers blessing and bond of stone are also defensive they aren't picked to be defense for you.)

Everyone is doing more damage. Assassins were already killing people without this damage increase so now it frees up room for tanky or even more brawler items. There is no reason to play a glass cannon version of a champ when a more bruiser/tanky build kills as well, with more health on the way out.