Bees in the bonnet time...
Every year for the last 10 or so years when a new Pterry book is published, I find myself wondering; who will replace Vetinari? It would be out of character for the character not to want Ankh-Morpork and its allies to continue to thrive therefore it seems unlikely that he would leave his replacement to chance. Who is Vetinari keeping an eye on as a possible successor? Who is being trained for the role without necessarily being aware that he or she is being trained?
For a while I thought that Vimes might be a candidate, but I think that he is perhaps too much of a late-comer to low politics and altogether too honest and straight-forward and, if in charge, would lapse into authoritarianism. Carrot is likewise far too honest, although he has shown disturbing signs of subtlety. However he more or less explicitly ruled himself out as a possible ruler at the end of Men At Arms? Guards, Guards? I forget which.
Of the other characters Von Lipwig is the only one that seems to be cunning enough to survive as a politico, but he doesn't seem to have that core of logic, I was going to say cruelty, but there's no maliciousness in Vetinari's decisions unless you are a mime, that allows V. to stand back and see what is the best, or least worst, course of action.
Drumknott? No. I think not. A man who prefers constrained problem domains. It also seems to me (and I've no idea why this should be so) that Drumknott and Vetinari are of an age.
Ah, well. Perhaps the question will be answered in the next book.