Hunter did mention that the further one goes back in time, the more severe the side affects are (bleeding through the eyeballs, nausea, vertigo, blindness, etc.). So I guess we are to assume going back 4,000 years would be potentially lethal and out of the question.
You both make good points I hadn't thought of, thanks.My thought was the further back in time you try to eliminate him, the more you will change the timeline. If, as they implied, he was the driving force instigating many of the wars down through time, if you killed him before he starts World War 1, then World Wars 1 & 2 may never happen or happen at significantly different times. By the time you get back up to present time, the world may look radically different.
Perhaps Gideon is the 22nd Century version of Siri. Everybody with an iPhone has one.I'm still trying to figure out why Gideon is the ship AI. Does this mean Captain Rory Harness Hunter is a relative of Thawne or he stole Gideon from him? Does this mean another crossover with Thawne and even more Flash-timeline messing up?