Ok, i see your point and i agree. It's clearly different from actual disease that are destroying the proper function of our body. it's more of an unwanted by product of evolution. But i wouldn't be surprised that one day we will still call something like,say, a low IQ, a neurological disease. Who knows.

Regarding evolving immortality: I do think that even with our imperfect baggage, there's still a lot of ways for us to optimize by tinkering with what we have.