The Preamble isn't vague about what it's doing, though. It's quite clear. It tells us who is establishing the Constitution and expressly states the purposes for which they are establishing it.

Saying that those stated purposes should inform constitutional interpretation isn't a particularly novel idea. Pretending the ratified language at the beginning of the Constitution doesn't matter because taking it seriously might be inconvenient isn't a serious position either.

The possibility that judges can abuse constitutional interpretation is an argument for doing it carefully, not selectively. Or, as Joseph Story put it: "The circumstance, that so construed the power may be abused, is no answer. All powers may be abused."