If memory serves you align with me in that Genisys is actually an entertaining guilty pleasure sort of movie but in no way is it worthy of being taken seriously alongside the first two. So will this film even manage that...we'll see.
You know I wouldn't even call Genysis a "guilty" pleasure. Just a non-canon one. It's harmless and fun enough for me IMO. Enough so that I actually did want to see where they went with the story next. Hated Jai Courtney and the CG helicopters of course, as well as them spoiling everything in the early trailers. That said I haven't actually watched it in a good three years now so for all I know I'd see it again and say what was I thinking and then throw the blu-ray in the trash, lol.
But yes I'm definitely wondering if TDF will even reach Genysis levels of mindless fun. From the spoiler bits I've read this doesn't sound at all like anything Cameron would have written had he been allowed to continue the trilogy in 1994 or 95. Hell it sounds like he's *already* distancing himself from *this* film *more* than he did from Genysis!