Currently, Witness vote weight is all about SP. I do recall @ned mentioning about changing it. You can see the overall layout here.
http://www.steemreports.com/witness-voters/
The report gets rid of the proxies I believe, so it's basically how the SPs weight all distributed among the top Witnesses. The website also has sections for the lower 50s, etc.
Also note that I believe a significant of Steemians DO NOT vote.
I can see that I still have a lot to learn, and my questions are many. The only real pathway for me seems to be, "Keep Swimming, and Be Careful."
And really, most of your other questions can be found by visiting @paulag's blog for her stats. In short, there are upcoming @haejin's and many tiny circlejerk rings.
I get daily messages from Steem.chat about vote for vote.
As for @dan, the history is carved into the blockchain, you can read about why he left.
As for why did whales, et al wait? Again, Witness voting distribution should have answered most of that question.