There seems to be indeed an arc build up if you tie all games together starting from MoF. The new fighting game dropped something regarding this religious war didn't it?
That's the whole idea of what 13.5 is, the religions are fighting over the faith of the human village, who have lost hope due to the incidents.
Which seems like a fitting end to this whole 'religion' arc.
Hell, you could call this arc the 'Kanako is behind it all' arc, considering everything except SWR and GFW [Which also has nothing to do with 13.5], is, at root, Kanako's fault.
MoF, Obvious
SA, Kanako tricked Utusho into eating Yatagarasu, wouldn't have happened if not for Kanako being in Gensokyo
UFO; Rin's gysers she started due to Utusho released the Myouren Crew, would not have happened if not for Kanako tricking Utusho
TD; The whole awakening of Miko was catalyzed by the faith of the Myouren Temple right on top of their burial site... which wouldn't be there if not for the events releasing the Myouren crew... you get the picture.
Everything in the main games since MoF has been tied to Kanako's doing. It's a stronger theme than the religion <_<
The ironic thing is Kanako's whole SA plan of 'Get nuclear fusion get awe get faith' backfired
horribly and gave her two new groups of competitors.
So, if Touhou 14 is part of this arc, and it dosen't end with 13.5, it's ultimately going to be Kanako's fault.