Motivation is key.
Ford, like Arnold before him, chooses to die for the greater good and out of guilt for what he's done and what he failed to do. That dramatic connection, between those characters, is deliberate and powerful.
Ford may well be seen in future flashbacks (Hopkins fee permitting) but for him to have survived, even as a host, would be weak.
"Here I am dying for this... oh wait! Just kidding!"
The producers are (I believe) better than that.