The problem with this approach is akin to the free rider problem. That is, some people will continue to communicate without attention to the written, asynch, nature of the medium. Whole messages will consist of a word like "hmmm" or "ugh". This puts the burden of extracting the meaning of "ugh" on the people who do make an effort to add context and eliminate ambiguity.
I see no way to solve this. Only so much shaming can happen before communication becomes toxic.