I just don't want skinny pigs to be stereotyped as the whole breed is guaranteed problems.
There are always exceptions. I'm certain there are skinnies that live long, healthy lives. From all of my experience though I would have to say that it is the minority that does so.
Haired "mutt" guinea pigs can have problems as well but most of them live long, healthy lives as long as they are cared from properly. I know this from the vast experience of others that have owned GPs and cared for GPs. If I was to go on my own experience as my sole source of information I would have to say that guinea pigs are, in general, unhealthy animals. I have only had 1 healthy pigs out of the 8 most recent that passed through my hands;
-1 female had ovarian cysts
-1 Fem had ovarian cysts and later genetic malocclusion and died during surgery to trim her teeth
-1 male has a reoccurring surface cyst requiring occasional draining/cleaning
-1 male (rescued lab animal adopted out) died suddenly of no know cause at only ~4 years old
-1 male (adopted out) has hair loss from a possible fungal/yeast infection (being treated with little success)
-1 female had mites and skin disorders and died from complications from treatment/stress
-1 female had mites, skin infections (last known as cured).
As you can see my personal experience is very different then most people's but I cannot use my personal experience alone to judge the species. Either we have very poor GP genetics down south or I am extremely unlucky (or rather my guinea pigs are). My experience is a small drop into a large ocean of info and I rely on the "ocean" to form my judgements rather then my personal drop into that ocean. Your experience is the same way--one drop. We have to rely on the ocean of information over one or two personal experiences.