When I think "trendy guitar playing" I think of the instagram shredders who post 20 second clips that inevitably includes a sweep + tap.
I think the biggest trend I've seen of recent times has been the guys who are doing the shred thing with the single/split coil tones with mild distortion, the Plini/Tosin/Polyphia guys. I don't dig most of it, but I'm stoked that the younger generation getting into guitar has these guys as a starting point. When I started it was Nirvana, Weezer and Green Day that my peers were into. Now the kids are starting off with all this technical/prog/djent stuff and regardless of my enjoyment of it, the bar has gotten a bit higher than it was 30 years ago.