Mages Lost Their Identity To Assassins
Mages were always supposed to be high-damage, AoE casters - maybe with some crowd control or utility - but predominantly an AP Carry. But that has been largely untrue for quite some time. There is not a single thing within the entire mage role that cannot be done by at least a couple of assassins except one thing: being universally easy to kill.
The mage role has been almost 100% eclipsed by assassins.
High AoE damage?
and 
Poke?
is one of the best (although Zed can also Q 1500 units off a shadow, which out reaches Ziggs and Xerath)
AoE CC?

Wave Clear?

Engage?

Zone Control? Ha. The very presence of an assassin is zone control: you get near them, you die. Usually almost instantly.
And none of these are even exhaustive lists. There are 4 positions out of 5 with assassins in them - everything but support.
Most of these champs out-damage mages even in terms of AoE . Assassins are supposedly high-risk/high reward. How are you high risk when you dominate lane just by being an Assassin? How are you high risk with higher base stats, front-loaded damage and (sometimes multiple) escape spells that basically every mage has to burn a 5-minute cooldown just to match?
The scant few that don't dominate lane by definition from the start (
and
) just have to wait until 6 before they - you guessed it - dominate the lane by definition
"but assassins fall off if they don't get a lead"!
Bullshit.
are the majority of the game's best split pushers. Only dedicated split push champs like Nasus and Jax (who make real sacrifices in other parts of the game) can even come close to contending with them.
"b-b-but assassins take skill to play!"
Wipe that argument off your shoe before you come indoors, please. It reeks. Skill is having good positioning, and assassins - with the lion's share of escape tools - don't get punished for being in the wrong place. Skill is farming well, and assassins can make up an approximately 18 minion deficit (that's almost 4 waves) by going all-in at 6 before you even back to buy items. Skill is being able to manage mana, and how many assassins even really have that? Half? Is it even that many? Here's a paper towel to wipe your argument off. I didn't realize you fed your dog something sticky.
So what role does this leave mages with? Well, they utilize their massive vulnerability to provide the essential service of contributing gold to enemy assassins. Without the humble mage, assassins would be forced to actually farm until late game before heading off to a side lane. Like those peasants who play Jax
So for all you mages players out there who, like me, just have too much pride to play the easy I-Win-Button champs: My hat is off to you. This post is only here so you can read the salty comments by all the assassin mains as they desperately struggle to justify their (Lee) sins. Really. It's not like Riot will address the issue: they only let assassins be out of meta for a few patches before picking off the things keeping them out. And look on the bright side:
At least we're not ADCs. Or worse yet -
players. What peasants. :p
and
more than anything on that front because they're the leading providers of it. Hell,
is an aoe burst mage with absurd stuns.
is the KING of zoning...or emperor I guess.
and
weak aoe champs.

is a fighter. If you build her burst you can kill someone in 1 q and 1 auto.
and blow up waves with a ranged spell like
or