Agreed, if the problem is “Boosted (insert creature here)” is a problem, when the non-boosted dinos are not, then the problem is with the boosts.
I have a bias against creatures doing swap-in damage at better-than-instant speeds so I voted major nerf to Rhino (partly because that seems to be the only real thing going for it, so it would essentially need to be reworked) but coming from a mid-game player, could someone tell me why Monolometrodon and Sarcorixis are so vilified? I sometimes use mine, both of which are completely un-boosted, and even the boosted ones I face at level 20 or less are about as powerful as other boosted dinos of their level but nothing terribly special. What is it about these creatures that inherently make them so horrible to face that they, not the boosts, would need nerfing?