Simplest way to play AOM campaigns with patch 2.8 changes?

Long time ago it was possible to just rename a file and then play all AOM campaigns with the latest EE patch changes and new units like the greek physician.
However the developers changed the file structure of the game and that old method is no longer possible.

What would now be the simplest way to play the campaigns with the latest patch changes?
Would it again be possible to rename/replace some files to get the latest patch changes in the campaigns?
Or perhaps to extract the campaign missions as single scenarios and then somehow change what patch version they are using?

Thank you for helping out.