Yeah “lets teamfight” doesn’t always cut it. Currently I try to do as you said, and then green ping or thumbs up ping when it’s off cooldown, but I’m not sure allies always get it.
Edit: Just to add I find people underestimate how long 8-10 seconds really is. I ping fountain up in, let’s say 9s, and allies go straight in, I assume thinking that by the time their health is low my fountain will be up. A lot can happen in just a few seconds.
I really missed the question ping today. Our Adagio was holding down midlane while I was helping bot, and I wanted to ping 
at him to try and ask if he was all good for a second while I was covering because Kestrel needed to recover. I found it was overall more useful than toxic anyway. Besides, if your teammate is really doing some dumb shit then they deserve to be 
'd.
Also I really like the dual-meaning ping.
I don’t mean to beat a dead horse, but I wish we could preset our quotes from a list of “acceptable quotes”
For example, as a roam, I really wish I could switch “I need help” with “On my way”, but there’s plenty more instances where it would work
Spread out would be my main wish.
(Celeste/Vox and other aoe heroes killing half my team because they clump in poa silver)
Split push.
Take the turret
Take BC/GW
We need a “I have lagg don’t team fight” quote or something similar…
“announce ping” y’know, like the health + energy one, but for ping.
is better a “DOn’T TEAM FIGHT STUPID SH1TS I HAVE L4GGG”
¨Problem is there will be a delay on allies receiving the ping because of your lag…