I think it would be interesting if CDR was a support specific stat
Most of us agree that itemization and runes are out of control right now, so this isn't a holistic fix for addressing that, but I think that only putting CDR on support items would draw better distinction between roles. The idea of this is that other roles get better items, while support roles can use their abilities more often and it's more about the non-damage effect the abilities have instead of the raw numbers.
Now this doesn't hard lock roles out from taking support items or vice versa, but tanks that take the normal support items will be squishier, and damage classes that take them will be wiffle-battier, so we're just left with support on a budget trying to buy expensive regular items.
or
in exchange for raw AP/AD would just push these items more toward dumb "press all spells on the enemy in one rotation and you are done" gameplay
Damage AND
Armor Shred AND
Chasedown AND
CDR AND
HP
Damage AND
CDR AND
map mobilities AND
Chasedown/disengage speed AND
armor pen