Mages need 2 new items
recently
was buffed. and to be honest.. i love the new item and i don't think it needs any changes.
but i do think AP itemization is very weak at the moment. especially since AD got the new item 
and caster got nothing in response to two major AD item buffs
what AP casters desperately need is an AP item that build armor and mana regen, perfably with a unique passive of some kind, or maybe something we rarely see like 10% spell vamp (or w/e they are calling that nowadays)
something that builds from like 
and
and that build into some item that works as a halfway point like 
does, and then that maybe you can add 
to for a final item.
the other item AP needs is something to build out of
this is is VERY useful even when playing AP champs and it very annoying that its almost impossible to make use for as an AP because you can only upgrade it into AD, sure you can keep it un-upgraded for a time, but once you start to near endgame. and you have the gold its REALLY annoying to have your 6th item slot taken by an item only worth 1300 gold.
.