To me, it always seemed like HK-55's character was created specifically FOR the sub reward. Bioware knew exactly what they were doing. They took a fan favorite character (an HK droid), made a new incarnation, stuck him into the new story for a few chapters -- and then killed him off.
Then they told you you could get him back -- IF you subscribed for him.
That irritated me so much that I only actually played the chapter itself recently (I was subbed all along anyway, so I got the reward). Anyway, I'm not gonna sway anyone either way, but because of that, I fall in the camp of "let people have the chapter" -- or at least HK himself. KotFE is a couple of years old now, and new players should have a chance to resurrect him. He was killed as sub bait.