Problem with the terminator franchise is that it is difficult to outdo the creativity of the T2 liquid metal terminator. it is possible to create a super powerful robots but then it will be difficult for people to believe current technology can kill such a robot. but to create another new type of cyborg powerful enough to be almost unstoppable and yet still weak enough to be killed in a believable way, is where all the sequel end up hitting a wall.

T3: similar to T1 cyborg but with inner liquid metal that can morph into powerful futuristic weapons. actually still feel very much like the older cyborgs.

T4: human becomes the first prototype cyborg, and end up going against Skynet. errr... is this really terminator movie?

T5: human get infected by nanotech, and brainwashed into a new cyborg. but still pretty much feel like a T1 cyborg, its new ability is almost never used in any creative way.

T6: a cyborg who can split into T1 and T2 cyborgs. still feel like the old cyborgs.

Maybe they need a new cyborg which can download and brainwash people connected to VR gears or using a smartphone, so the identify of the cyborg is always hidden and everyone can be a suspect. hohoho.

isn't that age of ultron?