I was drawn to the Orks precisely because they have a fun and unique style compared to a faction like Space Marines which I consider to be sort of bland. I chalk up their lack of popularity to: Human super soldiers fighting for all of mankind are more relatable than dim-witted green aliens, and Orks are often used as fodder for Space Marines in the Black Library war porn literature. It sounds like maybe you just have a mental image stuck in your head for the Orks from the earlier editions where they were a lot more goofy. I think the current fluff and artwork portrays them as being pretty brutal and menacing if somewhat quirky.
I have never understood and never will understand on what the heck do people see on spesh mharunes. Seriously, bald guys (with the exception of space wolves, the coolest SM) with a way too fanatical attitude (I could include CSM in that too, I suppose) who remind me of some weird copy of star wars clones? No thank you. Will never even poke one with a big stick! Then... Orks. There will always be an ork somewhere. Or an orc. Or a gretchin. Or a goblin. ALWAYS!!!!
