This movie failed not because of horrible action scenes or whatnot, in fact it has some of the best action scenes in Terminator movies. What truly failed is the story, the writings, the characters, & the ultimate sin of franchise AKA destroying everything about the series.
It all bogs down to meaningless & convoluted changes & pretty much broke what made Terminator, "Terminator." It's very unfortunate when most of the part of the action scenes actually very thrilling & no awful jump cuts or stupid shaky cams like most of action movies this days.
Not including how the people work on the movie totally awful in promoting this movie, alienating the fans, & pretty much discouraging them to watch it.