Cooldown reduction is a ridiculously powerful stat for any champ that relies on their abilities rather than their autoattacks. It should be expensive and not found with other stats, especially defensive stats. Cooldown reduction on defensive items is the reason Sona had to be nerfed, it's what makes champs like Olaf, Xin Zhao, and Garen do stupid high DPS while building tank, and it needs to be isolated onto its own items.
Capping CDR should still be a viable build path, it just shouldn't come with huge survivability bonuses as well. It should simply make your champ better at their role, whether it is offense, defense, or support.