Is full-AD-crit Rengar considered bad for gameplay health?

Whenever I face a Critgar, I'm left wanting to smash that player's face into some concrete. Even if you see that "!" mark over your head, you have less than half a second to do something when he jumps or you're automatically dead if you're a squishy. It's not just the Q spam that'll get you, but the fact that he'll have an Infinity Edge crit and loads of bonus attack speed tied to it. Your only hope is to have someone like Alistar next to you when he does to peel him. And no, a Zhonya's won't work because you'll be dead before your input even registers, or he'll just kill you after you come out of it.

Even if you do have someone who can peel, I find it obnoxious when he builds so much AD and kills you in 2 hits, when other assassin's can't claim to do the same thing. Can something be done about his crit builds? Maybe make his Q crits not deal 1.5k?

EDIT: If you need more proof...

https://youtu.be/yW_st2H2Y2Y

Thanks for the link, Bussinessbacca.