[riverkid]

Coffa:
"If I were to say I love you, what would you do?" is the correct subjunctive mood form of the question. It indicates that you are unlikely to say such a thing, but you are speculating as to the person's reaction 'were you to do so'.

I'm afraid that this is simply not true, Coffa. "If I were to say I love you, what would you do?" is no more correct than "If I said I loved you, what would you do?"

More formal language does NOT equate to more correct language. That is an old canard. You noted in your post that "the most common usage is to omit the auxiliary altogether".

"If I WAS to say I love you, what would you do?" is the indicative equivalent, and traditionally should only be used if I am likely to say 'I love you'. However, this rule is the subject of argument, and in practice is not likely to be observed.

Note that you said "equivalent", Coffa and that it is. Language is much too complex to try to describe all situations with overly simplistic "rules".

If I say, "If I was Coffa, ..." does it entail that I think it's likely that I am you? If one says, "If I was a bird, ..." does it entail that that person or any other sentient person alive thinks it likely that the person is a bird.

There is no 'rule'. There is a prescription but when we look to how language is actually interpreted, it's abundantly clear that the 'rule' is completely bogus.

Don't take this personally, Coffa. I know that this bogus rule is not of your making. It is an old rule that long predates you but that hardly makes it an accurate rule.

And it's bogus for good reasons. Past tense FORMS combined with 'if', are used to effect a counterfactual meaning, "If I moved to London, ...". That is, as you note, a common method of denoting "subjunctive" moods. So it is with the past tense FORM, 'was'.

It's doing exactly the same thing that the lexical verbs, examples, 'play/walk/go', do when their past tense FORMS are used with 'if'; they denote a range of speech that doesn't simply denote counterfactuals but rather denotes a range that goes from 'doubtful to counterfactual'. Note that the true subjunctive forms do the same thing. They do not simply describe opposite to the truth situations. They too describe "a range that goes from doubtful to counterfactual".

Does this mean that 'was' can't be used to state, "allowing that something may have happened", as in,

"If she was at work today, then I must be blind"? No, of course not. But it's context that clues ENLs in to such a meaning and for prescriptivists to suggest that 'was' combined with 'if' always carries such a meaning is beyond disingenuous.