The most effective way of eliminating an evil government is by way of spiritual and moral reformation. The exceptionally corrupt and degenerate condition of the present-day Ummah does not entitle Muslims for a wise and benevolent ruler. The present mob of corrupt and cruel rulers at the helm in Muslim countries simply mirrors the moral decadence of the Muslim masses.
No method other than moral reformation and spiritual elevation will ever succeed in the endeavour to bring about change in our pitiable political state of misery and weakness. As long as Muslims flounder in moral corruption and in their anti-Sunnah lifestyle, they must expect to live under the yoke of oppressive so-called Muslim rulers and be disgraced by the kuffaar.
Rasulullah (sallallahu alayhi wasallam) said that the hearts of the rulers are between the Fingers of Allah Ta'ala. He turns their hearts in whichever direction He wills. When the Ummah submits in obedience to Allah's Law, He will either mellow the hearts of the existing rulers transforming them into just rulers or He will eliminate them. Their elimination will pave the way for benevolent and wise ruler.
Rulers/governments attain their appointment by Divine Decree. It is Allah Ta'ala Who appoints the rulers of countries. In the Qur'aan Shareef, Allah Ta'ala says:
"Verily, the earth belongs to Allah. He grants its rule to whomever He wishes."
"He grants dominion (political power) to whomever He wishes and He snatches away (political) power from whomever He wishes."
In terms of Qur'aanic and Sunnah teachings, rulers are the reflections of the deeds of the nation. A spiritually degenerate people will be saddled with a corrupt and oppressive regime. A spiritually and morally refined nation will be blessed with a benevolent and wise ruler.