Does brand feel really weak to anyone else?

I had around 500 ap and was still unable to one shot an adc with no defenses, I don't really understand. I seem to do the big damage as soon as I get 3 stacks and the pop does barely any dmg, the shortened burn duration hurt him really bad and unless people are really dumb you're not gonna land your combo and you can't have the same harass you used to. He barely does any single target damage anymore and he can probably shine in teamfights but with all the MR items these days and how weak he actually feels I doubt he could do much other than harass enemies down to half hp.