Good Trists are good.
I am copying that build and learning quicksilver sash.
Anyway, I've decided that the three champions that I cannot deal with are as follows:
Sion. He becomes a tank with huge lifesteal with barely any lifesteal or health items. He becomes nearly invincible if he's continually hitting enemies.
Fizz. He's impossible to get a hit on with any AP caster. He'll just dodge it, and then use his ult, which does much more damage than anything you can muster.
Morgana. She also becomes a tank really quickly. If one gets a RoA, you're screwed, simply and bluntly. Then, after that, she continues to do as much or more damage than you can while continuing to tank.