Notice, how the "Senior" members who have argued this time and time again all agree that he hisn't OPed, while the "Junior" Members (who are probably low ELO, just from how they post) all complain about how much damage he does.
All (ALL) casters deal high amounts of damage, Veigar, Annie, Ryze... its their job, they're Squishy though, FF on them and they become nothing more then a corpse. Everyone is complaining how the casters (And Jax) are OPed, and really, their not... they just need to be attacked from a different angle you guys are approching from.
Ryze needs to be taken down first, or CCed long enough for you to get outta dodge after he pops his Desperate Rune Prison. Not the blind/slow CC, silence or stun. Most casters have a weakness like this, Annie's threat level drops after she stuns someone, Ryze's drops when he uses his Ult too soon, Fiddles is useless if he gets FF on (1.8k hp end game, atleast last time I used him... Ryze with a similar build has 2.5k). Jax, well, Jax is difficult to explain, he's not as easy as just to CC him. You've gotta keep distance between you and him (he hits harder after every 3 shots, keep him from getting those 3 shots.) In team fights, you can try and FF him, but his high HP may prove difficult (unless you're a caster, then you eat through his dodge).
You want your caster to take him down, if he starts getting magic resist, his damage and HP will be lower, so its a win win for you.
Can you please quit QQing on how all the casters are OPed please... Its their jobs, live with it.
PS: oh and Tim, I do that too. Trying to use more commas, but I always think I need a longer pause.