Allow us to ping our spell cooldowns for our team

How about when you alt-click the spell, a little indicator shows up above your champion's head, with the icon of the spell, along with a ring around it that shows how close it is to being off cooldown?

So when you're playing Ezreal and your solo queue teammates think you're dead so they don't bother saving you, you can show them that your E is about to come off of cooldown, so they shield you and help you get out alive.

Or, imagine you're supporting bot lane with Sona. Instead of typing "I'm going to all in right now," ping your Crescendo and move forward. Your ADC will know exactly what's going through your mind.