
Max M. answered 08/05/19
Harvard Literature major with 20 years of coaching writers
"As if" takes the subjunctive, so the correct answer is that "were" is always called for.
However, the subjunctive seems to be fading from common usage in English, and "As if it was..." is becoming common, so if the trend continues, you will be less and less likely to be marked wrong for it. I would guess within a generation, it won't be considered an error at all. And hey, language changes, and that's all fine, even if I personally don't like it.
And really, there will always be a linguistic need for the subjunctive, so it's not really as if the subjunctive were (ahem!) disappearing; it's more accurate to say that English is gradually adopting "was" as the subjunctive form of "to be" in the singular, instead of "were."
But for what it's worth, there is a shade of meaning being lost, and it's exactly what you say. It probably seems blurrier because of how common the non-subjunctive syntax is becoming. "As if" will always call for the subjunctive because it's describing actions that might take place, rather than those that definitely are (or are not) taking place. But other "if" forms can go either way, and here's an example of why that's going to be confusing.
Take the Cowardly Lion from Wizard of Oz. He sings:
"If I were king of the forest..." which tells us that he's not king, but he's imagining a scenario in which he might be. But:
"If I was king of the forest..." describes a very real possibility that he used to be king.
So if "were" becomes "was" in the subjunctive, a future Lion would only sing "If I was king of the forest," so his listeners wouldn't know which meaning he intended. Sure, they could figure it out from context eventually, but "were" makes it clear right away what's on his mind.