Let's get straight to the point. Kentrosaurus is going to be a cut above. It's piercing gaze alone will be enough to send even the largest carnivores running. It will slash the competition. Tribes would be foolish not to stick this in their arsenal. It may be a hard tame, but I'll take a stab at it. Did I mention that it's pointy?
They should be able to go into wall mode almost like turret mode and be able to act like a spike wall when in this mode. Like an enemy attacks and they just stand there spiking them and inflicting bleeding and a bit of knock back.
These dudes are actually quite good for the dragon boss fight, they are herbivores, are very tanky and have a high melee, also if the dragon bites them it gives recoil damage, only bad thing abt them is they can't have saddles