Seriously, what is not to like about this item? Mana, AP, CDR and even movement speed for those slow mages.
Most importantly you get a strong Sheen proc for 50% of your AP, so as a mage you have damage in between your cooldowns with your basics.
It helps with faster tower pushing as well.
Seriously, everyone going full AP should consider this item.
Death by Glamour6 votes3 things
its pretty expensive and simply not worth the bad build path to rush in a lot of cases
a lot of AP mages don't need to weave an AA into a combo
To use the passive you have to be in AA range, which is pretty dangerous for a lot of the mage
Full Brain1 votesNot usually worth on really long range mages who aren't going to be in range enough, ability spam mages like 
, or ap tanks since they just don't have the space in their build. It is really something you consider on like a mid range moderate cooldown mage or kiting ap characters like 
.
macspam1 votesBecause other items are more essential. For mana/cdr there are haste items, for dot there is rylais and liandrys, for defense there is banshees and zhonyas, for mpen there is void staff and morellos, and to cap it all off (no pun intended) theres deathcap. So yeah lich bane is pretty good but that gold can go somewhere else. On cassiopeia for example once you hit Q, your E does 60% AP on a like 0.5 second cooldown. So theres really not much a need there.
