Gretchins aren't con. How I could build things without their little fingers? And they are smarter than normal thick'ead boy so they can invent something on their own too. But thread related, orks believe in eternal war so much that they (or Mork and Gork) rule this universe without them realizing it. Gork/Mork keeps Emperor alive so humies could keep fighting, Mork/Gork prevent Slaanesh from devouring all pointy ears so Kommando boyz would have challenges, GMork called tyranids so boyz would have something to beat and grow up before fighting beakies.
Death to filthy Xenos, Orks are indeed the worst enemy they didn0t wage war for surviving, for some god/deamon or for conquest but only to fight a brutish race that deserves only exterminatus
Everyone in the galaxy? Very likely yes. Unknown against Tyranids though, as they are not from our galaxy and their total numbers are still not known.
Cons to being orks? THERE ARE NO CONZ! Ye're green, red goes fasta, ya got dakka, ya got WAAAGH!, wot'z not ta like? Sure orks die, but we diez fightin', which is 'ow all orks should die! In short, even if orks have flaws, like not being the smartest, they're the only race that's happy about the state of the galaxy. Well them and chaos but still. Just war, war, war, and they wouldn't have it any other way.
Dere's wun Con. Wez kan neva get enuff Dakka. Whyz do ya fink we lootz? To add mor dakka dat uva races ave! I wunce ad wun of dem Nekron Eavy Gorz Shootas strappt unto 3..no 4 Bigga Ork Shootas an' a Cannun dat launched Bomb Squigs! ...Wut 'append? Well it blew up and killd all da Grotz in it. But it lookd like a Creashun dat Mork'd be proud ov!
