Let's discuss AP itemization
Now, after meme-ing the mage circle jerk let's actually discuss the "issue" with mages. Which is the lack of diversity.
The items fulfill their job and mages are performing decently well but over the past few seasons AP itemization has become stale and extremely unsatisfying, especially compared to AD ones.
So, instead of whining over Mages being "weak", let's talk about the actual problem that is mage itemization:
Problem numero uno: Mages are forced into the same core build
Burst, Control, Assassin, every mage builds basically the same nowadays with 
being extremely common, especially Morellonomicon just being "too good" as it just provides too much for its price and thus condemns other items to be mediocre and unsatisfying.
It's so good that I even started rushing it on Mordekaiser.
https://www2.pic-upload.de/img/34017251/Bildschirmfoto2017-10-02um11.05.07.png
https://www2.pic-upload.de/img/34017254/Bildschirmfoto2017-10-02um11.05.01.png
Which leads me to propose this fix: Introduce more "core" rush items for mages that cater to their specific needs and niches. Currently Morello is too good on every AP champion and just feels mandatory.
I suggest adding items similar to the ones in Black market brawlers, albeit with changed stats, that support certain AP play styles.
Pox Arcana for example being core on AoE and burst mages with Netherstride Grimoire being used on kite mages. Make these items unique, making mages unable to get all of them so that they're not just getting stacked with enabling passive effects. Most of these items should have mana, though CDR should be given out more sparingly, especially to burst-oriented builds.
Problem numero dos: We need more item variety in terms of Pen and battlemage itemization
With preseason mages are losing some mpen and unlike lethality and armour pen, MPEN is only present on three items 
And even then these items don't really seem to support certain niches but are rather mandatory.
I suggest we get more items building out of 
, providing certain end game items to fill niches like Tank-busting (%bonus Pen), squishy bursting (Flat pen) or sustained damage needs (Basically AP black cleaver)
Rylais too, has to be reworked imo to better support a sustained damage play style and I even suggest removing the permaslow for a windowed, more flexible and skillful form of CC on the item.
And numero tres: Some items need to be heavily retuned and their niche has to be explored better
Deathcap in particular needs a component item, or rather a "mini rabaddons"
Tear can use some rethinking too
And lastly, a rule of thumb, which I think should serve as the main rule when reworking Ap itemization: #High AP values should not be matched with CDR
Sustained damage mages should opt actively into CDR and burst mages should prioritize big, juicy AP values. There's a problem where EVERY mage gets 40% cdr, it devalues the importance of certain high impact spells and makes mage niches overlap.
buffed while making it healthier
spellvamp would be appreciated
instead of 
). I just like being able to play a risky build when I want to.
every match
and 
for one, except ranged auto attacks and AD damage.
and 
despite both being hailed as lategame hypercarries.
rework involved transforming it into basically an MR Sunfire Cape that reduced the MR of nearby targets with each burst, stacking a few times. So Riot has already tested a potential AP Black Cleaver and found issue with the idea.
. Tanks have been complaining that MR is too burst-oriented and does not do enough to prevent sustained magic damage for 4 seasons now. Sustained damage mages have enough power in their kits, they don't need a special item.
/
) and assassins are supposed to kill mages if they manage to close the gap. The mage has to peel for themselves and soften the assassin up at range in order to kill them.
and
but they are choosing the higher AP options over those. That's not because the CDR options aren't good. They're amazing. Mages of all stripes just prefer raw damage output.
