I have CDR for Glyph rune only, maxing CD for her is giving up alot of damage/armor you've had. Other than wanted to resealth faster, she doesn't benefit as much from CDR since her CDs are short to begin with plus I play her AD. Buying CDR items is a waste in compared to damage/defense items because once you out of stealth, you need to make sure you get the job done or at least survive. Only item wth CDR I ever buy for her is ghostblade because it comes with arm pen and speed for chasedown/escape.
CDR is extremely valuable on almost all champs, especially on champions with short cooldowns.