I've only seen up to T3, but I wasn't expecting it to be a fitting addition to the series. Truth is, I don't really get bent out of shape over inferior installments to popular films.
With Terminator, they should have slowly distanced itself from Arnold due to his age and limited acting ability -- that is, if they're striving to build off of the first 2 films. I realize Terminator's scope is limited, but so was Planet of the Apes to a certain degree. They could have expanded upon the iconography beyond having to rely on the aerial drones and giant tanks alone from the original films.
I just think that the directors from the non Cameron films left much to be desired, as well as the studio mandates to include more humor, camp, and self aware irony to their films. I know that saying that the sequels needed better directors is a foregone conclusion, but I don't think Nolan could have saved the script from Genisys. There needed to be a serious reverence to the material and I don't think that ever came into play.
