Don't know how to reply to this without stepping into that "beautiful" field of eugenics... ugh...
Baldness;
does magic recognize bald "gene" as "defective" or "normal"?
My vote would be normal. The only "unhealthy" aspect of having a bald head is that it increases your exposure to solar radiation and thus increases your risk of skin cancer...but that's not really enough to matter in context. (Especially if
cure disease can treat cancer.)
Obesity:
would magic remove the unneeded mass of fat, or would it change genes to make your metabolism faster and slow down "storing" of excess energy into fat tissue in the future?
Getting fat is evolutionary trait to survive lean winter months with very few food around. So maybe it would make you even more prone to getting fat as insurance so you do not starve in the winter.
My assumption would be that it would distinguish between amounts of fat-storage that are benign but not necessarily socially accepted, and those which actually contribute to noticeable unhealthy symptoms (like sleep apnea, atherosclerosis, type 2 diabetes, liver malfunction, etc.) Different options present themselves depending on how the curative magic works, but I think I would prefer something like a temporary metabolic rate increase to "burn off" excess calories. The patient might even experience this as a fever if they don't go out and
use that energy for something.
Albinism:
what is "correct" pigmentation? I hope no one continues this part....
Perhaps treatment of albinism would require a donor of some kind, such as an unaffected blood relative.
Alcoholism/addiction:
does character trait op personality trait falls under disease or defect or is it just variation?
Well, one of the treatments for alcoholism is basically a pill that blocks the feel-good chemicals that come from drinking alcohol. (There are different compounds which perform this function, with varying effects; often it is best as a second or third line when other therapeutic methods have failed.) So perhaps a spell could just turn off your ability to feel good as a result of consuming alcohol or whatever drug is in question. Intoxication without positive feelings would generally suck and that could, in theory, quickly curtail the addictive behavior.
I'm really lazy, i try to fix that, but most of the time I fail and I would take a pill to "cure" that if it were available.
Is being lazy a character trait/quirk or mental deficiency? ahahha!
No, but there are actual mental health conditions which people can easily
confuse for laziness, such as executive dysfunction (basically, an inability to actually...
do things, even when you KNOW you need to do them, even when you WANT to do them) or time management disorders (e.g. ADD, ADHD, and autism-spectrum disorders all frequently feature disruption of the subject's ability to manage, estimate, and coordinate time and tasks). "Laziness" is, more or less,
choosing not to do something when you easily could, whereas the above issues are a mental or physical block which inhibits the ability to make good on one's choice to do something. Like the difference between cowardice and PTSD; the former is an elective pattern of undesirable behavior but not in itself a mark of ill health, while the latter
is a mark of ill health that can disrupt one's life and lead to undesirable behavior.
Sickle cell anemia:
this would be simplest. Genetic defect, there is no upside to having it.
I mean, there's no upside to having albinism either, and it too is a genetic defect, the inheritance of two genes that both fail to produce
any melanin at all.