I personally grew up hearing the set phrase
If I were you... (not
Were I you, which somebody quoted as a "stuffy" example). I did not have to learn about the subjunctive in Latin or Italian in order to use this form, but it's true that when I studied the subjunctive in those languages I did understand the difference better. Learning one language is often a help in learning another, although we should not allow a revival of that absurd, mystical idea, that you
must study
Latin in order to understand your own language!!
You have to take account of reality and the fact that a large number of native speakers do not regularly use this form. Nevertheless there are plenty of people who do still use it and it can't be considered archaic.
I teach it to my students as they will sooner or later encounter it, in reading if not in speaking, but I also tell them about the real situation among native speakers and that using
I was all the time is not a serious mistake and perhaps not a mistake at all nowadays.
As for
I wish.., a Pink Floyd song comes to mind (but no, that's 2nd person).
Just to be clear:
She is here - real present
If she were here - unreal present
She was here - real past
If she had been here - unreal past
If he were rich he would buy more clothes. Unreal present
If he was rich, it wasn't evident from the way he dressed. Possible past