Why pantheon is so ****ing OP?

Well, look at this and read my build.
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Pantheon can kill who he wants and where he wants after lvl 6-9 if you do all things right.
Pantheon is stronger against squishy champions at beguining and stronger enought to rape who he wants in a secund at the end game.
He got a lot of amor penetration and a lot of atack damage, if feed, he can kill a tanker in 2 or 3 seconds.
Exhaust? Why not Ignite?

Well, Exhaust in pantheon is good at 0-10min, but exhaust is very good from beginning to end and usefull aganst ganks (if you put a point in Cripple, Exhaust will got 10mag and 10arm penetration, and incresed duration 0.5)

PAY ATTENTION ON THE MINI MAP
The most important think is wathing the map with attention, because you are able to:

Defend ganks on mid or your junger
Gank mid in a few seconds
Use your Grand Skyfall as a teleport and def or atk towers

Pay attention when you try to kill champs that have a lot of crowed effect, like fiddle.
Your damage is Heartseeker Strike, if they stop it, just run away.
The other problem is, pantheon need to farm or get all kills, because if he is under power, you will lose the game, he is amazing uselees without good and expensive itens.
You can be ****ing strong with a suppoerter in your lane, the best support for pantheon is Janna, Blitz, Sona. (I prefer Blitz.)