Udyr Still Strong or Just Plain Bad After Nerfs?

Strong.

he's... alright right now. Though now he kinda needs to use the shitty feeling AP build, and that'll only be worse in 6.9 when devourer gets thrown in the trash and getting removed takes another 20 ms off him.

He's still strong. Same with Master Yi.

Riot only love taps champions, they never completely gut them as I've seen them all be useful, even in higher elos like Master where they are all played as well, including Master Yi despite people saying high elos never pick him which is false. He has success there too.

Udyr's problem is the attack speed from Tiger Stance. That has always been the problem Riot doesn't want you to know about. They have you thinking it's the Phoenix Stance and others, but it's that massive attack speed he gets. He can clear the camps faster than anyone practically and be ahead of the Solo Laners by 20 minutes by 2 levels.

Master Yi's problem is his ultimate gets resets practically on kills/assists. Take away that, his ultimate would be a much high risk reward only good Master Yi players will make use of.

I don't think Riot has truly nerfed a champion to the point where they are unplayable. Sejuani is still decent, Aastrox is annoying and can go on killing sprees quite easily after a few items, and if he itemlizes right, you won't be able to kill him.