I feel like the purpose of the infamous question mark ping has changed a lot since its release, and don't really like this development.
In almost all cases, it's used to signal teammates' discontent with a play, instead of missing enemies. For me, it is becoming increasingly difficult to tell if actual enemies are MIA, or if someone just wants to vent his anger over the ping wheel. Not only is this extremely annoying and demoralizing to deal with, it also affects the game negatively by confusing your teammates and twisting important information on what is going on on the map.
I don't know if implementing another symbol for "enemy is missing" would help, but I want to ask people to please not use the question mark ping in that way.