I believe the Clan has a rather strict caste system, with Goblins on the bottom since they are the easiest for everyone to push around. Conflicts between classes/races are quire common, not that clashes within one are rare. Members of the Clan have more of a group mentality than the Doviello, so what would be a one on one combat there here escalates to clashes between large mobs.
Orcs are the descendants of Humans loyal to Bhall, and I think that Goblins are the descendants of Elves although there is a small chance they are instead descended from Dwarves. I think that at least some goblins (like Khmer Otterfig) are smarter than the majority of Orcs, but I'd guess the disparity is less than in Warhammer. The disparity between Orc and Goblin intelligence would be no greater than that between humans and Elves (which is probably quite minor and comes only from elven longevity allowing them to learn more over a lifetime, even though most elves prefer to think that they are naturally far smarter). I suspect that Goblins are not naturally smarter than Orcs, but that Orcish culture discourages intelligence while Goblin culture admires cunning. Goblins are skilled at using poison and cunning tactics that Orcs wouldn't consider honorable. (I think Orcs are a proud people that care a lot about honor in a Klingon-like fashion, while Goblins have no such scruples.) Goblins probably consider themselves to naturally be much smarter than Orcs, but are mistaken in that belief.
Lizardmen are among the abominations creatures created by Patrian mages (possibly Kezef himself) by combining humans with animals, but since humans were the base they are still descendants of Nemed and thus possess souls/divine sparks. I believe that they tend to be as smart as humans, and smarter than the average Orc. They tend to be quiet and mysterious, not nearly as social as Orcs or Goblins. Ogres and Hill Giants might fit into this same category, but I'm thinking they actually have no human ancestry and are thus really just soulless, dumb animals.
Ogres may be much stronger than Orcs, but I believe that they are about as low in the social standing as Goblins because even a below average orc is smart enough to trick them into doing just about anything. They are the dumbest members of the Clan, and their low numbers mean that even if they had the capacity for tactical thought groups of Ogres would be overpowered by groups of the weaker races.
Bhall Orcs are the top caste in the Clan. The Clan of Embers is basically defined as those barbarians who are still loyal to Bhall and her priesthood, so this is the one Clan class missing from the Barbarian State. The Priestesses of Bhall and their relatives are probably weaker than most Orcs but still stronger than Goblins, and much smarter than anyone else too. They are descended from the Age of Magic's Bannor priests and nobles, while most orcs are the descendants of commoners or from humans of other nations. They still speak the noble tongue of Old Orcish, a beautiful, passionate, poetic language that is more closely related to Bannor than Common Orcish, as it was what was spoken in Braduk before Bhall's fall. This tongue is also known to some Shamen, who I suspect come mostly from the makes of this same lineage. This caste is more civilized than most. (Human sacrifice is a civilized activity, right?) I suspect that Rantine is descended from this caste, but was himself not a priest as the priesthood was female-only until Jonas became its High Priest.
Orcish warriors and self appointed Warlords generally seem dumb, but those we know the most about are actually rather cunning. Sheelba probably comes from the line of Bhall Orcs and she was raised by humans, so it could be expected for her to be above average intelligence. Jonas seems quite smart too though, and from what I gather he was but a common warlords before he killed a priestess of Bhall and was made into her priest. I don't believe he was born into the line of Bhall Orcs, but he is of course their high priest and thus the lead Bhall Orc now.
The idea in the Minor Leaders thread is actually for allowing him a second Warrens building, only affecting Goblins. So 4 goblins at a time. 
Probably have to give some 'Uninspired' promotion to all non-goblins....
