Just never let anyone tell you that a Carnosaur is bad. If you do a little effort to build the army around him (like clever use and gearing up of priests), and kit him out extra he is hell incarnate for the enemy. The true streangth of the carnosaur is the element of suprise. When people hear "Lizardmen" they tend to think "Life/light/shadow Slaan and a bunch of Temple guard, and they are largely not on guard to deal with a carnosaur rider. Here's how I use my carnosaur
Oldblood
- Armor of destiny
- Dawnstone
- Great Weapon
- Carnosaur
- The other tricksters shard
Since he's a saurus, and most of the army will be sporting the same LD as he is, you can safely put him on a flank. Then use a fast unit, preferably cold one cavalry (with a scar veteran if youre feeling cheesy). This combination will punch through pretty much anything from large monsters to elite fighting units. Use the priests to support them from a range. I normaly don't use an engine of the gods, since taking it, an extra priest, a scar vet to be youre BSB and optionaly a scar vet to run with the cavlary is impossible to fit in, so i'd stick with two priests with Staff of sorcery/Diadem of power/Cube of darkness etc etc, which gives you a fair magic defence. The other flank is supported by an anchient stegadon and a trio of salamanders, which gives the enemy warmachines a double take as to what they should shoot at, and it gives the saurus the extra support they need to hold on untill my cavalry and carnosaur can smash through the enemys flankers and charge into whatever the saurus are fighting.
As for the warmachine debate, I know these things vary from area to area, but I'v only faced warmachines once versus skaven, and he blew himself up on the first turn, so I don't really see them as that much of a consistant threat.
The Carnosaur lends itself to far more dynamic gameplay than the Slaan ever could, and winning due to your t-rex tearing apart the enemies deathstar with a unit of raptor riders backing him gives a far more satisfying feeling than you´re Temple Guard grinding them down due to the silly buffs you´re slaan cast on them.