The subjunctive: The ever-present confusion between tense and wish

I’ve been an editor for many years. I have the following question because it’s so utterly frustrating: Am I plain wrong, have people changed their ideas about acceptable usage, or are people just careless while using the subjunctive? A seemingly reputable site tells me about conditionals in the context of wish / potential:

#1: Present: If I have the money, I will visit Japan.

#2: Past: If I had the money, I would visit Japan.

For these, I’d say (OR "I’ll say"?):

#3: Present: If I were to have the money, I would visit Japan.

#4: Past: If I were to have had the money, I would have visited Japan.

What never fails to perplex is the seeming interchangeability, for many people, between tense and potential. Referring to the above sentences insofar as the subjunctive serves to indicate potential, #1 sounds plain goofy. About #2: For me, saying "If I had" implies I did indeed have; I reserve it for cases such as "If I was rude, it was only because…" Along the same lines, statements of the form "If I was King, I’d ban smoking" occur so often as to make me wonder whether I have it all wrong. Shouldn’t it be "If I were King"?

In sum: How can "If I was King" even exist as a phrase indicating a wish/potential?