if you're in a position where 1 g.pie will kill you and the mage wants to blink into a bad spot to finish you..you probably fked up way earlier.
I do think it's broken.. over 2200 I find I spec it may 50% of the games? I know some really high ranked mages the hardly ever spec out of it but outside of Rogue Mage it's pretty hard to consistently get set ups on people.
short version: if you're always getting hit by g.pie and you aren't playing against a mage rogue comp, you're kinda messing up.