This isn't a bad idea. I mean, GEO and RUN are getting AF that will be Lv. 109 and will most likely come with some crazy stat boosts and enhancement buffs relevant to GEO and RUN respectively. So it would only be fair to give the other 20 jobs a new AF set (AF4) that is also Lv. 109 along with crazy stat boosts and enhancements relevant to them as well!

I also like the idea of combining the 3 AF sets to form AF4. Great idea! It would force people who skipped out on doing the original AF quests (which is nearly everyone nowadays) to do those quests. It would make Dynamis relevant again (farming AF2 pieces) and it would breathe some life (albeit temporarily) back into Abyssea seal farming and +2 item farming. All these things mentioned are older events that most people would be able to do solo or in small groups and is not an impossible task to complete.