You are right, I forgot that old bloods get4+ scaly skin. Old bloods are so expensive though. If you would consider old bloods as a magic item, you pay roughly 75 points (if you also take into consideration that their cold one and GW are more expensive) for an extra WS, an extra attack and an extra wound. An oldblood dies to combat resolution and a bolt thrower, magic missile or cannonball just ad hard a LS a regular scarvet. I find that they either are completely overkilled by something like the pit of shades, or are impervious to the many strenght 4 attacks be they get in their face. I think those 75 points are better spent elsewhere. What I meant about the carnosaur is that I think that the main advantage of the old bloods is his 100 points magical allowance. If you want to go full monster mash with him as the huge beater in the center, he gives you a lot more options if you take him as your general without a slann. In other situation I think scarvets are, point for point, just more efficient than oldbloods. Carnosaurs have their own problems I agree, they really want to kill other monsters or monstrous infantry, but they do have their uses.