I also quested (won) an Ophidian, early in my first game. It accompanied my sovereign for a while, and died a couple of combats later. On the whole, I wasn't appalled by this outcome ...
Okay then. Maybe they could start at Level 2 instead, as a compromise?
I think StevenAus's suggestion is a good one. I would expect that Ophidians (tame-able, and usable, by humans) would be a little more useful than dogs or wolves, but not as powerful as sand golems.
But looked at another way, I view all of these units as "expendables" -- not really permanent units. They are not champions or armed men; and I would not expect them to take the place of such units. I'd think of them as useful "accessories" (mostly for the sovereign) in the very early game -- not as units that would level up, and stick around, for a whole game.
BTW, anyone else think that henchmen are over-powered ? I guess that might depend on whether or not you like to play Altar ...