It's just not sustainable in the long term. Because dictators can at some point, turn mad. Or say if the next Saudi King, turned into Joffre.
Without checks and balances, these dictatorships ultimately collapse on themselves eventually, I don't know many dictatorships that don't either become a massive problem, or exist on a timeline that is extremely shaky in contrast to the rule of law and democracy.
Sadam wasn't what kept the terrorist organisations in check, it was the governance, the control. When he was removed, they didn't erect a power structure capable enough of keeping the terrorists in check. We created a vacuum and they took over in those ungovernable spaces. This isn't just the mid east that happens. Think about all those warlords in Africa. They exist because of ungoverned space.