Yeah, especially since they are no longer ST7, taking warriors just seems like a better option. They may not hit as hard, but you have rank bonuses and command and many more attacks, especially if you use spears (and you should). To be honest, I've dropped them to take terradons instead, even though I love the Krox models!
I prefer to think about the kroxigor as a gigantic unit sergeant, since he improves their leadership and gives more attacks. The real advantage of the krox is psychology. Charge a unit of spearmen and the skinks will give crazy combat rez, but if the enemy hits on 6's then your fine, the skinks still hit as hard as empire guys typically. (and krox helps) Plus, the krox can soak arrows 1/3 of the time.