Regarding the leg example: Yes definitely. The model is also not intended to be applied on a specific disease but rather about being healthy in general. Although it can be applied to specific diseases (e.g. depression).
First of all: Thanks for opening up. I've read your post; very interesting story. Regarding the 100% getting over: I'm not sure if it's a good perspective on this issue. I don't think that there is a state where a person can say I'm 100% free of depression (or for that matter, psychological issues in general). Some people have certain traits stronger than other. You might have some social issues while others might have issues regarding being aware of oneself. So I personally belief it's more about just saying "ok that's me." and that's it. No rating, just accepting oneself and not thinking that I'm abnormal or something. You can do this if you showed me this normal person that you are different from.
I find the feelings you describe interesting if I may say and I believe that there a lot more people out there with these kinds of feelings than the average person thinks there is.
I'm sorry but I would like to disagree regarding your sentence "This world is more so for extroverts". I think it's, again, more a matter of the perspective. Introverts do have a lot of advantages in comparison to extroverts. I think it's sometimes helpful to look at personality just like we for example look at skin color (not the old fashion way). Can you say a white person is better than a black person? Or that he has it easier than a black person (generally speaking)? Everyone has its traits; one has more of this the other more of that. The traits we were born with don’t make us better or worse people, but rather what we make out of these.