Is Tryndamere op?
I think he is.
I think he is.
Does he have over powered parts of his kit? Absolutely. Does he have parts of his kit that are significantly weaker because of his insanely good ult? Yes.
There are so many things to counter him.

I watched a video today where a guy split pushed as Tryn, died 18 times, only got three kills, and still had a gold advantage on the enemy laner for a significant portion of the game
Possibly just an indication of player skill, but, food for thought
He is only OP against people who don't know how to deal with him. Knowing when to stop him from pushing and when to group and fight are important against him. This is why he is strong in low elo and almost worthless in high elo. If you build tanky and don't feed him early game and know when to group with your team and when to stop him from pushing, he is rather easy to beat.
Yes.
He is extremely OP. He spins in and rages and is all like YYYYYYYYAAAAAAAAAAAAAAARRRRRRRRRRRRRRRGGGGGGGGGGGHHHHHHHHHHH!!!!!!!! And then PENTAKILL! and then turrets and inhibs and Nexus and he's all like "My right arm is a lot stronger than my left arm"
Way OP needs nerfs