Riot should really copy Dota's cooldown ping system.
For reference, in Dota you can hit the ping button and then click on one of your abilities to instantly put that ability's cooldown in chat.
Now, Riot recently added rudimentary allied ult timers to the HUD. However, there are two big differences between the two.
- The Dota system lets you ping any cooldown. Jungler trying to gank and you just blew two abilities on the wave but they didn't notice? Now you have a very easy way to tell them that you can't follow up, rather than just back pinging and hoping they understand what you're trying to say.
- You can communicate intent. Having ult timers passively on the HUD is nice, but they're always there so people don't necessarily take notice of them, and even then knowing that an ally's ult is up doesn't mean you know they're about to use it. If you ping that your ult is up, you're communicating an intention to actually use that ability, which cuts out a lot of stuff you'd otherwise have to type in chat.
I had a situation where a system like this would've been incredibly useful earlier. I was playing Shen, and my midlane Yasuo was in a situation where it looked like he could go all-in but it would be incredibly risky. Now, I could always target ping the enemy laner and hope he gets the message, or I could actually say in chat "Yasuo my ult up go in", but the first is unreliable and the second means that you have to stop and type something. Stopping and typing something, even if it's only for a second, can be a liability since it locks out your abilities. If I had just been able to do something like target ping and then ping that my ult was up, I would've been able to communicate that entire line of text in two pings and like a quarter of a second's worth of mouse movement.
Letting people ping their cooldowns would allow for a lot more instant communication between allies, which would make solo queue teams where people are actually playing well able to react better to what their allies are actually doing. Instead of just engaging on an enemy and hoping your allies react properly, you can communicate exactly what you can and cannot currently do to those allies, which is incredibly useful. If implemented properly it wouldn't really add any complexity to the game itself, it would just add the option for players to communicate more information without having to type. I think that a system like this would greatly benefit this game with no real downside.
tl;dr dota lets you use the ping button to instantly put ability cooldowns in chat. League should as well.