I think some are getting confused by Minions new higher attack attack and defense values into thinking they are simply doubles of other creature types that for the sake of fun gaming, are given 1 HP and said to die in some grisly one-shot heroic blow from heroes. That is not the idea. Minions, as described in the original
excerpt about them, are actually replacing the traditional mooks or lower level creatures that a DM would throw at parties, but who would be routinely ignored because their stats didn't scale. Minions in 4e were originally going to get a small number of HP even to represent their
weaker nature, but the bookkeeping this brought back in made this pointless.
If a group of monsters had a giant royal rumble outside the concern of a party, minions would
not abstract into having normal HP and possibly killing other brutes, soldiers, or leaders. They would die and be wiped out every time just like they do in a battle vs players. Because regardless of 1 HP being a small abstraction, they are still meant to be the weakest fodder troops in the mook role and should in most cases be identifiable as such. They are weaker in both threat and appearance, just like they were back when a DM was throwing 20 level 2 Ghouls into a fray as filler in a battle against Wights, Mummies, or some more powerful challenge. But because Minions can now come from the same races as an even level challenge, some people are confused as to what they represent, or that a party would somehow be unable to tell these vastly weaker creatures apart from more powerful ones.
That would be akin to making those 20 Ghouls used in 2E or 3E as fodder, look exactly like the Vampire Lord who is the real boss of the encounter. Which would of course be folly and destructive to the coherence of the game in many ways. The fact that Minions now in 4e might be Vampires as well, does not mean they are indistinguishable. Got to stop looking at non-descript miniatures and use some imagination. The Vampire Lord probably looks like
this guy, while his Minion’s look more
like this.
I think the game gains absolutely nothing by trying to purposely create role confusion of Minions amid combat. It actually dilutes the tactical nature of the system if anything. I don't ever recall in 2e or 3e thinking that a combat against 6 Ogres would be made so much better if a bunch more equally offensive Ogres were mixed in but who only had 1 HP, with the player's not knowing which were which. 4e says now we have some 'Ogre Thugs' you can use, but who are probably less armored, equipped, smaller and weaker looking and who few will confuse with the bigger nastier brutes who dominate the clan and are the real threat to players.
What Skills could a Character use to Identify which Enemies are Minions?
Monster Knowledge checks (Nature, Arcana, Dungeoneering, etc) as per the PHB, should yield their Name,
Type and Keywords on a DC 15. Assuming at least one player is trained in the relevant skill, this is going to be a gimmie in most cases. If combat is getting dragged down every encounter by rolling a lot of these formality skill checks, a DM might consider the value of just pointing them out as a matter of course, except where there is some reason to expect the players are unfamiliar with the foes and enforce the rolls.