Yeah, anyone who'd be worth a damn is "Too Powerful for Dead Thrall".
That and he leaves a skeleton upon death.
TodKarlson wrote: How well do they perform Dead Thralled vs Summoned?
A dead thrall will stay with you until it's killed and a summoned/conjured being will expire within a few seconds. If a powerful dead thrall is capable of being raised, they are much better then summoning something to fight with you.