But how can a housecat kill anything? It does 1d4-4 = 0 damage with a successful hit.
If you're talking 3e, that housecat does at least 1 point of damage, by the rules (a successful attack does at least 1 damage). If 4e, a housecat doesn't even have stats normally, so they don't do any damage unless the DM says so.
I just think the 4Ed Minions mechanic does a poor job of simulating this because, as I said, 1 successful hit from a PC and they're done...which not only doesn't comport with the RW, it is also at odds with heroic genre fiction (at least, the better exemplars).
If you're talking written fiction, there's Song of Roland, where he's cleaving Saracens are getting cleaved in two left and right, or Conan hewing through lesser men by the dozen in some of his earliest tales (early as in "young conan" not "first stories Howard wrote'").
If we're looking at movies, there's the Lord of the Rings, where literally DOZENS of "one-shot kills" are portrayed. And in TV, good old Buffy and Angel might stake a minion-seeming vamp roughly once an episode.
As for the whole, "50 cent and Phines Gage" analogy - they don't have to be PCs to not die in one hit; all told, "regular monsters" are faced at least as often as minions are. I'd say look at it deductively rather than inductively; because minions can have just as many skills, defenses, and close to the same attack bonus as non-minons, then the real test is: if they died in one hit, then they were a minion. If they didn't, then they weren't.
Alternately, a DM who doesn't like minions can either substitute them out for a non-minion at a 4-to-1 ratio, or make them non-minions pretty easily. Using the chart on page 184, convert them to Brutes, as that seems to be the closest category in terms of defenses, attacks, etc. to minions. Give them the brute's hit points, a normal or high damage expression, divide the number of them by 1/4th, and you're in business. All the other stats are close enough for government work, and those two steps are all that's needed.