Sutekh is the real life Egyptian God of violence and chaos, not just evil. Thats how detailed the Egyptian evil is, they have gods for each specific bits of it. So it makes sense, then, that hes also one of the most powerful Doctor Who villians of all time. The only thing that could defeat him was the power of another Osiran (who are a real people in the Doctor Who universe - the new series says Satan exists too, so it's obviously taken the Indiana Jones route of saying all religions are true at this point). Even the Time Lords couldnt stand a chance. As testament to this, he almost keeps the Doctor in a ten trillion year long life of agony using only his stare and, although he was trapped in a pyramid by weird Osiran forces, that stare was still so powerful that it could contain entire explosions.The Daleks stare is somewhat less formidable since in their first adventure its stare ends up being obscured by a coat.