The white hulk of the Lizardmen, Gor-Rok! Chakax is cool, too.
That would be unlikely. On the TT (at least in 8th ed) he was a worse version of Muzdamundi in almost every way. He was more fragile, was useless in combat, had no stegadon (or mount of any kind unless you count his palanquin) and was not perticularly useful as a caster (due to having 1 spell).
Kroak is just a Mazdamundi 2.0 but undead. His presence will eclipse Mazdamundi and this is very bad i think.
I think, if anything, the main issue with Kroak is that he is obsolete as long as Muzdamundi is around.
Well Mazdamundi cost nearly twice as much as Kroak on TT, so it's not like Mazda being better is unwarranted or shocking in any way. Kroak did have other uses though;
- He made a unit of TG fully unbreakable while being unbreakable himself whereas most Slann just made them stubborn and ItP
- He had a 3++ Ward save compared to the standard 4++ of other Slann and Mazdamundi
- His Death Mask caused a -1 to hit for attacks directed against him or his unit since the mask essentially made him the Hypnotoad
- Finally, while he only had one spell, it was an absolutely filthy spell, especially against Daemonic or Undead enemies.
And this is only based on his 8th edition rules which, when compared to previous editions, were pretty bare bones (pun 100% intended). There's another 4 items that he had in previous books, a slew of other rules, and his own personal Oracle, Ten-Zlati. Considering all the material there is for him, he truly is a character unlike any other.