Funny how the only class who can't really abuse Transcendence is the Mage class...

Mages dont really have that many cdr items as people think.

Because there is only 2 AP items with 20% CDR and both of them are unique passives so you can't stack them. That and as Ahris has mentioned, there is actually not as many AP items with CDR as people keep pretending.

Morellos = 20% Hourglass = 20% CDR boots = 10% Transcendence = 10 cdr

so yeah you're going over by 20% over the cap which translates into 40 extra AP. That's sacing some magic pen by not taking sorc boots too. So yeah, it's pretty meh