Removing any punishment isn't vague - just take it out of the hands of those who can currently inflict it:
1. Make it illegal to fire employees for any speech in the public square.
2. Make it so they have to be found guilty in a court of law in order to be fired or shunned for anything sexist or racist.
3. Make it so that any publicly funded institution (even partly) cannot terminate their relationships with individuals because of their speech in the past or the future.
Right now what we're seeing is extrajudicial punishment instigated at the will of anyone with a twitter account and following. The above suggestions reduce the twitter mob's leverage because they shouldn't have any to begin with. Anyone seeking damages should have to go through channels that allow some kind of defense. The court system is supposed to be systemized thoughtfulness so we should rely on it.
The way I see it playing out is that companies will force all employees off of social media with their own names or fewer people will attack companies because they know that the company can't do anything. Both cases are a positive change.
You're being optimistic about vengeful people online. I don't think you're being realistic.