You say each has a "well-known and mostly consistent history behind it"
None of these have a consistent history, being subject to the whims of changing panels and ideological en-banc fights every couple years when a new judge gets appointed.
You act as if they are well thought out, well applied doctrines, when they are completely hit-or-miss bullshit that has caused the MPEP to explode due to the inconsistencies.
"I'm guessing this is going to make the PTO's and Federal Circuit's job even harder and more inconsistent."
The federal circuit needs no help becoming more inconsistent, they do a great job on their own.