I previously used a Markdown meta data field named "url" for creating linked list posts. In Pelican 2.8 that field was just ignored because it conflicts with the Pelican meta data for a post. In Pelican 3, it throws an exception and halts the script. I fixed the problem files but then I noticed that Pelican 3 processes posts much slower. What once took under 30 seconds to process took over 10 minutes under Pelican 3. In fact, my hosting provider killed the script because it consumed 90% CPU on a shared host. That's what I call "less than ideal".
To revert to the 2.8 version try this:1
That downgrades the version of Pelican and fixes up the easy_install files. Of course I needed to restore my Pelican config.py file too, since Pelican 3 expects different feed parameters.
I'm still thrilled with Pelican. In 30 seconds I was able to revert to a previous state and get on with life.