Champions

[Anzekay]

Sion is beastly. You need to have either a strong AD against him (which will be weak against ganks without support due to sion's stun) or gank him a lot early game. If he starts building that AP, he becomes extremely difficult to kill. The AP ratio on his shield is very high, 'bursting it down' is not always an option, in paticular when he has just stunned you. And let's not forget that even AP Sion gains a lot of life steal with his ult up, that's enough to keep him going before his next shield/stun combo.

So yeah, sion is by no means underwhelming.