It was a good enough super power for the main thug in The World is Not Enough.
Yeah, all of which are plausible problems for the most plausible superhero.
No, it ain’t. The problem is power-supply. The black-box power-plant that runs the suit (and Stark’s heart) does not exist, and IRL, no portable battery or fuel-cell yet invented could keep that thing going for five minutes. And, of course, even if that problem were solved, the suit still couldn’t fly.
Korean War hero Ace Morgan shot down a bunch of enemy planes before becoming a record-breaking test pilot; that’s not a power, or even a “Batman or Iron Man” backstory of debatable implausibility; that’s just being John Glenn; a number of American aviators shot down enemy planes in that one, and a number of those aviators went on to become record-breaking test pilots. (What, you’re going to badmouth Iven Kincheloe? Don’t badmouth Iven Kincheloe.)
Anyhow, he promptly teamed up with an Olympic wrestling champ who knew how to handle a gun (and, again, real-world America in fact had just such a gold medalist at the time: an Army veteran who’d joined up with the NYPD to, y’know, fight crime and save lives); for bonus points, throw in a scuba-diving explosives expert and a mountain-climbing sharpshooter; in short, the Challengers Of The Unknown were essentially four guys with mundane skills and conventional firepower, cooperating with the authorities and sensibly carrying sidearms when setting out to arrest crooks.
(This being a Jack Kirby comic, they’d of course arrive with guns at the ready to find the crooks du jour had only just now stumbled across wacky alchemical concoctions that granted weird super-powers, or whatever – but that shouldn’t count against our heroes; they were still just a team of gun-toting athletes.)
Clint Barton/Hawkeye. If you dedicate your life to it, you can be that good an archer. Bow-controlled arrowhead-selecting quiver? Completely plausible with today’s technology.
First of all, I would like to note that Googling “plausible man” (without the quotes) gives some very odd results.
As to the OP, I might have to go with The Coon.
Krokodil:
Psychologically, I can definitely see someone who saw his parents murdered by gunfire not wanting to have any association with guns. I agree that practically, using a gun would help him a lot, but I don’t see his refusal to do so as “implausible.”
I think most non-powered heroes of the Golden Age are pretty plausible. Sandman, Atom (before he got his “atomic punch”), Wildcat (before he was ret-conned to have nine lives), Mister America, the Guardian, the Whip and a host of others were simply skilled hand-to-hand fighters or users of devices that are downright mundane or not unreasonable for 1940’s technology.
Plus, while no killing might not be a completely inviolable rule, Batman does go to great lengths not to kill people; shooting someone is pretty much accepting that they might or probably will be killed.
We’re talking Cartman here, right?
I also vote Kick-Ass.
But Jimmy Olsen gets an honorable mention.
Oh, and so does Kamandi.
Yes. Is there another superhero named The Coon out there?
Plausible man, plausible man, doing the things the average man can. What’s he like ? It’s not important. Plausible man…
I lol’d. 
The Lone Ranger. His superpower is the ability to shoot the gun out of his opponent’s hand, without killing him, or even causing serious injury to the hand. Very nearly plausible.
Peripheral-Vision Man!
I would vote for The Wizard of Oz or his current avatars, Anonymous, Lulz-sec, etc.
Normal humans with hidden identities, reputation for power (with the hackers, used for their questionable definition of “vigilante justice” ), ability to keep regular humans off guard and perform seemingly huge feats…all with a little bit of humbug baked in…sounds superhero-ish to me…
I hope not. That’s what I wanted confirmed.
Silk Spectre I.
Her chief ability was teh hawt, right?
Man-Man. He was bitten by a radioactive man, and has gained the powers and proportional strength of a man.
Reminds me of Man-Man, the superhero who was bitten by a radioactive man, and thus obtains all the proportional strength of a man his size.
Dammit, beaten by 2 minutes!