Having an everyman character allows one to relate more to the character. And just because he has powers doesnt make him any less relatible, its that fact he is a normal guy who just fell backwards into some super powers. Then people can look at it and say "Hey I could be this guy". Also seeing someone experience the same problems is comforting, gives a person the feeling they are not alone
My argument has always been that Peter Parker wasn't that normal a guy when he became Spider-Man. He was skinny and small and he wasn't attractive. Not to mention, he was a complete and utter genius. I'm failing chemistry and while I'm not Tom Cruise, I've been on plenty of dates. I can't relate to a character like Peter's.
Peter didn't become the 'normal guy' that everyone goes on about, until he became Spider-Man. Spider-Man gave him the confidence he needed to become more of a wise-cracking self-assured guy. This, I can relate to.
On the other hand, depending on what incarnation you read, Clark Kent is universally relatable. In post-crisis,
Lois & Clark and even today's comics (most of the time), he's a regular guy. Not the talk of the town, but not an ugly troll either. He's got a regular job, he has regular problems with bills, etc.
I can also relate to the more 'geeky' versions of Clark from over the years, because they're like caricatures of my own life. In the Christopher Reeve Superman movies, Clark stumbles over everything and stutters in his speech and stands out like a sore thumb,
in a bad way. Anyone can relate to this, because who hasn't felt like an goofball at times?
Then there's the Brandon Routh-Clark, who doesn't stand out
at all and nobody pays any attention to him. Don't tell me you never feel invisible.
Don't get me wrong, I
can relate to Spider-Man, but not as much as everyone else seems to be able to. Usually, I relate to Spider-Man when I'm having a really, really bad day. Spider-Man has always been able to laugh really bad days off, and that positive attitude rubs off on me and makes me feel better when I think about it.