Would this be a good time to mention that ROG-2000 is Axel Pressbutton: the Psychotic Cyborg from the waist down and Ultron from the waist up?
I really like Ma and Pa Kent being alive in the Superman era. While that's not especially original on Byrne's part, it had made for some good stories.
What's irksome about Ma and Pa Kent being alive is not that they were kept alive, but the REASON they were kept alive: to allow Superman to completely divorce himself from the disaster of Krypton, a disaster that it should be added, that is one of the saddest and most poignant events in comics which is the primary reason Superman, despite all his powers, is sympathetic. With the Kents alive as his "real" parents, the sacrifice of Jor-El and Lara (again, one of the most heroic and tragic stories in comics and partly the motivation for Superman's heroism) can be diminished and ignored.
Previously in the Super-Mythos, everything had a reason, everything present in the Superman story served a purpose. With the Kents being alive, Superman's origin suddenly becomes an afterthought; any other origin could be substituted for Byrne's Superman and
he'd be exactly the same character.
So, in conclusion, the survival of the Kents was irksome for two reasons:
1) They were intended to substitute the more captivating characters of Jor-El and Lara, which the Kents can never really do;
2) They were to function as "wise counsel" for Superman, which makes him look like a chump because he can't make decisions without asking Mommy and Daddy, and is also rather insulting to rural people, the perpetuation of the condescending "wise hayseed farmer" stereotype that talks in calf birth metaphors.