Are stuns too powerful

Are stuns too powerful. pretty much if you play anything but a tank its pretty much stun and done especially verse a full stun team. and most stun champs have that ability to smear an enemy champ with out... How is that fair? Example: Jax-> can 2-4 hit any non tank champion. He has stun and his invulnerability.
Panth-> stun...shield block...spear... that ult escape( not that he ever needs to escape Annie-> stun and that ap burst ... need I say anymore I can keep going Stuns are an overbearing part of the game; not that they aren't necessary or they last too long They are too much an offensive fixture for some of the champs that wield them. Defensively they are still sound. Stun and runs are still a great escape when needed; if needed. I think it would be a benefit of the game that when a stunned player takes damage that the stun end and they be able to defend them selves as best they can.