I just saw on the Paizo forums claims that Legendary Games is planning to release a 1.5 style edition of Pathfinder under the working title Corefinder. The following text was apparently taken from Legendary Games' Discord.
COREFINDER - This is Pathfinder Refined. It retains the core structure of Pathfinder 1st Ed and is intended to be generally backwards compatible with it, in particular on the GM side, so that existing PFRPG monsters and adventures can be used without the need for massive revisions. It has a lot more room for innovation and redesign on the player side when it comes to classes, feats, and spells. This is an edition that distills the very best of Pathfinder 1E - it fixes the broken, clarifies the muddy, purges the chaff, condenses the redundant, reins in the OP, improves the lame, and polishes what's already good.
It also has a second purpose, which is to extract the core essence of Pathfinder 1E to its Core (hence the Corefinder name) in a way akin to the 1980s Rules Cyclopedia for the BECMI series of D&D modules, and it will present genre-free core for the rules that can be adapted to any genre, PLUS a Corefinder Fantasy module that incorporates magic, magic items, and all the trappings of a traditional PF/D&D-style game. Whether we publish these as separate books or an omnibus is more of a logistical question than anything else, but we would like to have the root Corefinder able to be adapted to different genres and styles.