I wish I was/were there

I can see that point of view. But then I find myself doubting the present subjunctive, too:

1. The simple present is found in the same environments as the simple past.

2. The present subjunctive is not found in the same environments as the past subjunctive.

3. Therefore the present subjunctive is not a true subjunctive.

??

MrP

The present and past subjunctive are found in different environments... in modern English. They were more widely used in older English and some of these environments coincided. We have "If this were true..." (past subjunctive), but in Shakespearian English we have "If this be madness (present subjunctive), there is method in it". I'd say they correspond.*
The fact is that the subjunctive has been replaced in many cases, either by the indicative (if this is madness...) or by non-finite constructions (I want that this be done becomes I want this to be done). The residual areas of use may be different in the present and past, but I don't think this makes them different in principle.

*or is it "though this be madness..."? Anyway, there's also "If music be the food of love..."

And you're a teacher?  Of kindergarteners?

I'm not an expert, but I have been educated formally on grammar all of my life.  The "wish" usage is in the subjunctive tense, just like "If I were..." and although there are well known writers that use "was" that is simply incorrect.  http://www.bartleby.com/64/C001/061.html For formal documents and essays, I flinch when I hear "was" in the subjunctive form. 

I notice that some BrE-speakers (political interviewees, for instance) use both "if...were" and "if...was", e.g. in structures such as:

1. If it were necessary to do X, Y would...

2. If it wasn't for the fact that X, Y would...

I don't take this as a difference in register; there seems to be a tendency in some speakers to use the "were" form for remote speculation, and the "was" form for "counterfactual but quite likely" statements.

MrP

What you described is exactly how I first learned about the subjunctive mood; by studying French. Very interesting that you mentioned it here. Just to add two ideas about the subjunctive.

1. AV was saying that the past subjunctive functions differently than the present, and thus should be called something else. For what it's worth, in French, those hypotheticals are used with the Past Imperfect, and not the subjunctive.
"If I were" becomes "Si j'étais"

2. One thing that I never see written about concerning the subjunctive, although it could be that I'm looking in the wrong places, is how the auxillary verb of the present continuous in english can be affected.
"I wouldn't recommend that you be thinking about this all day."
At least for me, that rolls off the tongue quite easily, and doesn't feel forced at all.

http://www.google.ca/search?num=100&hl=en&q=%22that+we+be+thinking%22&btnG=Search&meta=

Not a lot of hits though with this example. Maybe it's just due to my studying French.

Jon