Shredders are Goblin built machines though.
Thing is, Draenei are pretty huge. Gnomes for example come up below the hips of male Draenei. If Gnome Tinkers inside mechs are slightly larger than male Draenei, than Draenei inside mechs would be by all accounts massive. Far more massive than any doorway, staircase, dungeon tunnel, etc. In that case we're talking huge issues with clipping, taking up visual space in raids, etc. However, a smaller race like Gnomes, Mechagnomes, Vulpera, etc. could be about the size of plate-armored male tauren and still give the effect of a character piloting a large machine in combat.
Let's be serious; It would be strange if you have a Draenei Tinker entering mech form, and they're almost the same size as a Draenei outside of mech form. That would immediately kill the immersion and look silly to boot.
Yeah, we were talking about Wildfire Bomb.
I think the more important point is that they're not pets. Also we were talking about Hunter pets. What you're doing here is playing semantics.
Semantics again.
Here's the point; We have Hunters that can shoot poison arrows and use undead beasts. We even have Void Elves who have a few Shadow racials that can thrown in the mix and even appear undead in appearance. To top it all off, Void Elves get
Entropic Embrace which has a chance to give their attacks additional Shadowfrost damage for 12 seconds. So as a Hunter, you have a 33% chance with each attack to enter this state and you'll be shooting shadow arrows for 12 seconds. They also get a shadow-based teleport.
IMO, you got your Dark Ranger. Like seriously, what are you missing?