Being a non-native speaker, I have always found the English subjunctive fascinating as I learned more and more about it. In fact, I have always been interested in the idiosyncrasies of English, though I am surely not aware of many of them. Trivial is not what makes a language interesting. By the virtue of my university, particularly my literature course, I had the fortune to come across Shakespeare's writings, which I wouldn't have been eager to read if it had not been for the course, because I have never been a literature lover. A plethora of unusual constructions, inversions etc., which even if they were harder to understand, they drew my attention. There were not just English, but beautiful English. But that is another thing, now back on topic because I digressed from the purpose of the topic to my personal interests.
In speaking, I certainly wouldn't have used the subjunctive in #1 and neither in #2. As about #3, I might have used it in
"unless he was", but I would have absolutely used it in
"if he was". But that just because I see it as 5jj calls it, a fossilized expression. I use
"I'd rather you didn't", "you had better not go", "as if she were", "I wish I were", "if I were", "it's high time he got a job" constructions in conversation, but I would probably never use the subjunctive in the usual if clauses. As about writing, I use constructions like
"it is required that he go (should go) there",
"lest you should miss the train" once in a while and I also use the subjunctive in usual if clauses, but just because I am by far more careful when it comes to writing.
I rarely hear or see the subjunctive used these days. You will probably not hear the subjunctive being used in nowadays films, tv shows or talk shows, but I remember hearing it in older, respectable films or masterpieces (in my opinion) as Harry Potter. I can partially remember it now, it was something like
"... Harry, it is important that you should go...". I think that it is more used in
BrE than in
AmE and that must be the reason we do not hear today very much, because the most films are American productions. However, the forums or websites related to the English language are the places where I found it fairly used. My teachers use it as well.
You may find it odd, but sometimes I smile when I hear it used where I when expecting it. I don't want to offend anyone, but I tend to think that it is more used by educated people in terms of language (academic) than by normal speakers.
Now it seems like it is vanishing and that is bugging me, people start to talk simpler and simpler, forget and forsake the beauty of the language their ancestors once spoke.