Old and overused suggestion but will this ever happen?
It just makes it easier and more accessible everyone, especially in what is a heavily team-orientated game.
It just makes the whole process more enjoyable and you can simply mute people as if it's normal chat.
You say that it's unlikely because of flaming and it's hard to monitor but that makes absolutely no sense considering that CS:GO and various other extremely competitive games allow for the feature
If you don't like what someone is saying, the logical option is just mute them and report them instead of limiting the development of what would be an incredibly useful and effective feature.