I think Salvation at least tried something new, but the actual plot wasn't handled well and such theme is not new to ppl.

The other 3 were simply copypaste from the first 2 with minor change and always comes with retcon.

T3 was decent but surely a disappointment following T2. Genisys was similar but turning John into the villain and spoil in the trailer was MEH. Dark Fate killed John from the beginning was also a big NO to me. The new cast didn't hold up.