On Fri, Sep 25, 2020 at 10:35:36AM -0700, Mike Brooks via bitcoin-dev wrote:
> -  with a fitness test you have a 100% chance of a new block from being
> accepted, and only a 50% or less chance for replacing a block which has
> already been mined.   This is all about keeping incentives moving forward.

FYI, I think this topic has been discussed on the list before (in
response to the selfish mining paper).  See this proposal:

  https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2013-November/003583.html

Of its responses, I thought these two stood out in particular:

  https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2013-November/003584.html
  https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2013-November/003588.html

I think there may be some related contemporary discussion from
BitcoinTalk as well; here's a post that's not directly related to the
idea of using hash values but which does describe some of the challenges
in replacing first seen as the tip disambiguation method.  There may be
other useful posts in that thread---I didn't take the time to skim all
11 pages.

  https://bitcointalk.org/index.php?topic=324413.msg3476697#msg3476697

-Dave