FWIW - I think my "linrot" may have been due to the "sensors" gnome shell extension (supposed to measure CPU temp and others). I was getting a crapload of these
May 08 15:55:04 xxxxx /etc/gdm/Xsession: (gnome-shell:824): Clutter-CRITICAL **: clutter_text_set_text: assertion CLUTTER_IS_TEXT (self)' failed
May 08 15:55:04 xxxxx /etc/gdm/Xsession: (gnome-shell:824): Clutter-CRITICAL **: clutter_text_get_editable: assertionCLUTTER_IS_TEXT (self)' failed
as described here
if I started the gnome shell in an xterm with the --replace option.
Others have noticed problems with that extension. I disabled it and things seem even better than before when I had just disabled the animations. I guess more time will tell though.