Brian, you raise some good points but remember that Amazon limits us to what is supported by the DevPay program. A few of the ideas that have been raised by those who have commented here don't take those limitations into account.

Also, trying to reach for perfection and make everyone happy may be impossible or at least impractical. Most of all we'd like to focus on development, and that means keeping everything as simple as possible. Hence our idea for a flat mark-up percentage.

Remember the resource pool from any mark-up is essentially reinvested back into open source development which the community benefits from.