Fourarms has no special abilities and his strength isn't that special. You could count his extra arms as a special ability, but he barely uses them! Which makes sense, because extra arms aren't that useful. And he's pretty strong, but Ripjaws and even Stinkfly can tear through steel, and Diamondhead and Wildmutt are also great at melee combat, so Ben's rarely lacking in strength. At least Humungusaur and Waybig are big! Fourarms has nothing going for him! In My opinion, he's less useful than Grey Matter.

I think half the time Ben gets the wrong alien is just the Omnitrix going "No, Fourarms is shit, here's a better alien"

Maybe that's the point. Different, but not enough to feel truly different. Closest to feeling both normal and super.

Having never seen the show, I still enjoyed this post a lot.

I didn't watch much of the show, but was it ever stated what the actual point of the watch was? My assumption was that it's actually intended as a genetic compendium and cultural research device. Something to catalog the myriad species in the universe and allow someone to directly interact with them as a member, it just coincidentally doubles as a box of super powers so a 10 year old or a petty tyrant would see it as an easy way to beat face.

Yeah, you're spot on. Azmuth designed the Omnitrix to break down interspecies barriers by letting people experience life as another species, and to preserve lost species for repopulation. There's actually an episode where Big Chill, one of Ben's aliens, gets pregnant and has babies.

Damn, I didn't think they'd actually open the can of worms that is alien reproduction via main character. Like I assumed it would be an implied option lol

Lucky, Necrofriggian babies are very independent, and naturally fly into space to feed on solar plasma. Ben was very lucky that Big Chill got pregnant and not a more social alien like Fourarms.

Oh another thing: There's an episode where Ben runs into two Vulpamancers - Wildmutt's species. Ben goes "maybe I can talk to them" and turns into Wildmutt. So that's Azmuth's plan in action: Thanks to his experience as an alien, Ben's first instinct is to reach out and communicate. The Omnitrix made him a more empathetic person. ...Even if vulpamancers don't like to talk much.