Just a small proposal that might bring Zilean's usage up. Since he is a support champ, being able to reduce an ally's cooldowns will be very effective, allowing champs to poke harder with things like Sivir's Q. Perhaps reducing the effect by a few seconds when used on allies might be a good way to implement this without making it too broken.
It would have to be a lower amount of CDR when used on others since quite a few champions would abuse this to hell. Maybe like casting it on an ally only reduces their cooldowns by 3-4 seconds instead?
Cause considering Zilean usually gets CDR items himself, and gets rewind down to a 5 second cooldown late game. There will be a TON of abuse cases late game.
ADCs have this thing 
to grab their own cooldown, especially 
with 
.
That would be the most ridiculous buff ever. Do you realize how much people would cry with Annie + Zilean on a team? They already bitch and moan about how "Annie is OP" nonstop. Giving her 4 instant casts + Tibbers would delete a team. As an Annie main I would love it, but people would cry. There's 50 other champions that this would be ridiculous on as well.
