I'm thinking a bit closer along the lines with Anoobis. Namtar gets progressively weaker with each form, and all except his last few forms are high-damage terrors with a unique assortment of abilities. I'm talking maybe one or two special abilities per form and much tamer stats for Horatio.
We don't really have a whole lot of multi-stage bosses in the game right now. Namtar and Anoobis are pretty much it. Besides, it's not like there isn't a strong similarity between Dragon Isles, Demonic Library, and Naga City forcing you to fight through a string of "bodyguards" before fighting the big bad.