Many orcs go the nomad or scavenger route where they equip anything they can, thus the tattered mismatch look.
Don't forget other orcs are organized and tribal. That's where our look comes in. Sure there are patches and stitches, but most of us where similiar armor designs with our own personal touch. Tribals also adhere to a militaristic hierarchy with battle formations and complex tactics.
On then topic of color, we've got green, black and grey orcs. So although I would be happy to chant alongside Urk Kuldar, not all orcs is green, but we still love you knuckleheads!