FWIW I vote NO
I keep slime files along with my lisp source and the .emacs file. They are very much separate from the emacs installation.
I have used emacs in linux env mostly but recently I have been using it in cygwin env
I update cygwin for various reasons and I see emacs getting updated. I can control that if desired, but I see no need to.
I don't update slime that often and I am pretty sure that would be more disruptive.
Also one is a VERY mature product other is not (that's just reality , not to be taken negatively)
I see very little gain and lots of issues
-Antony