That if someone who knows he has clean UTXOs simply wants "a little" privacy without the taint, Wasabi would be the better choice than choosing a mixer that will comingle his UTXOs with Mr. Heroine Dealer's UTXOs.
I disagree. People who don't care about their privacy don't normally look for privacy improving techniques in first place. Besides what you are saying is just an illusion of privacy not actual (a little) privacy. If anyone just wants mixing (eg. they want to prevent regular people from knowing their coins) they could just use the centralized exchanges they are already using to do that.