I support you in your initiative, and I hope you succeed in your efforts. I'm not sure this is the right forum to express my views, but here goes.
You cannot have an open membership policy, and still have a community. There must be a more rigorous whetting process in place before you allow new members to join the community.
Allow community members to flag spams, explicit content etc so that community policing is enforced. But don't incentivize members to do the policing. That could be counterproductive.
Disable self promotion. It works counter productive to your meritocratic goals. On the contrary, Steemit team can promote posts which they think is worthy of being promoted.
Take strict actions against copy right violations. Disable accounts of members who do not comply.
The list is certainly not exhaustive. Others can add more points if they wish to. In my view, if the following steps are taken, I think you'll be able to achieve the goals that you've set for yourself.