Also, I think you didn't consider the backlog problem with EB-6. If EB-6 was added, lots of people would immediately begin the process of becoming qualified investors, and lots of EB-3 workers would start the EB-6 process. Then the EB-6s would get exhausted very quickly and a backlog would start, even if they were given a queue separate from EB-3. That is exactly because EB-6 would be so much easier than EB-1, EB-2, and EB-5 to qualify for.
Even if my friend's EB-3 petition wasn't backlogged, I would still object to the idea that rich investors can hand-pick immigrants that they think will make them money, and practically just hand them permanent residency. If you were advocating a new temporary visa program for these people I'd be a lot more supportive of it. But, they don't deserve permanent residency more than the people already waiting in the various lines.