It definitely should be open source, and I have my doubts about the project. But I don't agree that the top 20 witnesses making a lot of STEEM is a bad thing. Whoever does the most work towards developing the platform/blockchain should get paid the most.
While some of the top witnesses may be a bit "lazy," they usually work several hours a day on STEEM-related tasks, if not a full work day, and receive much less than a normal salary to do so.
RE: Does Vote Buying Affect @steem-ua Upvote Weight?