In no particular order:
1) Even blind and without the force, Han's aim is pretty damn good.
2) If Luke was on Scooby-Doo, you just know he'd say "Jinkies" more than Velma (Picture it. You know I'm right.).
3) Hans father isn't a homicidal war criminal. Luke is like the George W. Bush of that galaxy far, far away: he gets sent by his father's friends to finish a war his dad started. Also, at the end of all six movies, Han doesn't find out the saga wasn't actually about him. Hate to break it to you Luke, but you're Mary Corleone.
4) Luke needs to sell his speeder (Speed-er? Scoot-er? Coincidence? I think not) to buy a ride on a ship Han won in a freakin' card game.
5) Luke hasn't got a clue what the Kessel Run is, nor can he do it in 12 parsecs (*Nerd Alert: In Star Wars lore, the Kessel Run is a space corridor running close to a black hole. If making the run includes passing through curved space, the distance isn't fixed; therefore, using a measurement of distance (a parsec) instead of time is feasible.).
6) Han would never bother to explain like I just did.
7) Han has the stamina to build a shelter while Luke just lounges around inside a dead beast of burden. And what is it with light sabers and fucking limbs? You can always tell when the Jedi are about because the place looks like a goddamned War Amp commercial. When Han shoots Greedo, he doesn't lop off an ear; he kills him. If some horned Yeti hung me upside down in a meat locker, I'd sure as shit do more then take his freakin' arm off! Luke deserved to die of frost bite for wussing out.
8) Corvette Summer or Raiders of the Lost Ark? When Ford was kicking ass in Clear and Present Danger, Hamil was doing voice work on Biker Mice From Mars. I mean, come on... it's like Hamil wasn't even trying. Okay, maybe The Joker was cool, but you're not going to see Harrison Ford signing comic books at conventions to buy food.
9) Chewbacca probably stank real bad but he was still cooler than a blue and white garbage can on wheels. I think living with R2-D2 would be worse than having your phone stuck on the "Hello Moto" ringtone. In fact, for those of you who think R2 was "cute," set your phone to continually play the "Hello Moto" ringtone and drop it into the office garbage can. I can guarantee you that within five minutes, Gladys, the mousy but cute receptionist, will be charging cubicle to cubicle, double-tapping everyone in her path with that Smith & Wesson .45 you never would have guessed she kept in her purse.
10) Even if he is a "scruffy looking, nerf herder," Han can do Leia without breaking the laws of Nature and Mankind. Five minutes after the end of Jedi, Han and Leia are knocking boots while Luke probably does some monkish meditation with three, dead, bluish-glowing guys, one of whom, is his dad. Plus, watching Luke interact with the Ewoks just creeps me out. It's like some pedophilic beastiality just waiting to go down.