I don't think it's a good thing to make us disease-free in terms of evolution. I think it's better to just cure the diseases that kill us ( long/short-term) eg. cancer, aids, ... or make us immoble for longer term ( parkinson, ..) Why? Because i think the best defense is a good immune system. You don't get a good immune system by staying inside and infection free and using medication all the time. Let people become s…
Even aside from evolution - we are reliant on our gut microbe to survive. Unfortunately, in some cases, what makes us sick is stuff from our gut microbe! We're literally a biome unto ourselves - and who knows what would happen if we removed all X. Our immune systems are pretty damn good at killing stuff off, and we've also seen that the elimination of worms (ew) from our biome may have cause or contributed to a number of autoimmune conditions.
This sounds very much like an unintended side effects scenario. I definitely agree that we need to eliminate lethal and incapacitating conditions. However getting rid of "all disease"... it may cause more problems than it solves.
And then there's the sociological angle too