Over the past year, the EOS ecosystem (which employs a similar dPOS) model has had the leadership positions change from mostly community and independent developers to large exchanges

Guess this makes sense. If they have to run a node anyway, they may as well get paid for it. Now that you mention it, I'm sort-of surprised that most of the exchanges don't seem to be running Steem witnesses. I wonder if Platform Independent State Files will change that...

To be honest, I'd almost prefer that to having a bunch of semi-anonymous witnesses, who - for all I know - might even be multiple identities for an even smaller group of people. No matter who the witnesses are, I think "back room dealing" is unavoidable, but I hope it will have less reach and impact as tribes and communities start to take hold.