Please, just add it as an option at all levels, and focus on designing engagements that scale properly be it soloing or going in with a 6.
I know your tryhards are going to complain, but to be honest, no one should be playing this game every waking hour of the day. Make content complete-able by all, but FASTER for your tryhards, people can then move on to other games while they wait for new content, and don't have to be here arguing for random ridiculous changes that aren't helping development.
Thank you.