> Without going back and checking, wasn't PF a fork of the open core of D&D/3.5e?
Yes, this is why it was often referred to (at the time at least) as 3.75. Mechanically, if you knew 3/3.5 you could almost jump in without looking at any rules in Pathfinder. It did change things around spells and classes (having its own being the biggest issue more than changes to the standard/common ones with 3/3.5).
Without going back and checking, wasn't PF a fork of the open core of D&D/3.5e?
> Perhaps more, because D&D 5 was in some ways (though not all) an explicit attempt to go back to earlier, less complex editions of D&D.
D&D/4e and 5e are pretty clearly the most simple versions outside of the simplified versions after OD&D and in parallel with AD&D (B/X, BECMI, Black Box, Rules Cyclopedia), and in many ways both newer versions are simpler so long as you only consider similar similar scope, though they have broader (but not a superset, because neither has domain management or divine ascension as a first-party subsystem, while BECMI has both and the Cyclopedia retains BECMI’s coverage of the former) scope.
5e seemed to be more an effort to restore flavor elements many perceived as lost from the very complex AD&D/1e through D&D/3e than to revert to simplicity lost (since the opposite was true) in 4e.