The % cut idea is a good one for other Steem front-end sites that could provide other types of context, interface, and content arrangement that would be more valuable for certain uses. Or to encourage a design that directly competes with Steemit but has alternative design and perhaps a better post editor.

If you use steemit.com, then x% will go to the author and the rest will go to Steemit, Inc. Steemit, Inc will take a percentage so that competitors have an opportunity to compete on price (or charge the same). The funds we receive will be redirected into a community driven development fund that can help bootstrap new features and services.

I disagree that steemit.com should have a mandatory cut as well. Though what would be interesting to see is an optional cut to fund a community fund, whether for development or other purposes. Posts with that option chosen could have some small unobtrusive indicator of that. Gamify it a little.

However, the @steemit account has plenty of funds to provide development incentives, why would Steemit need to skim the posting reward pool for such a thing?

By the way, Golos has started an initiative to encourage differing front ends for the same reasons in my first sentence. http://blogchain.golos.io/