The question is, if not him, who else? My choice is based on lesser evil strategy 
Consider the alternatives:
PML(N) … blunders, mismanagement, emotional decisions and greed for absolute power. Twice had a good opportunity to perform at national level and could not deliver. Had opportunity to deliver at provincial level at many times, cannot deliver. Ideally, PTI and PML(N) should have negotiated and struck a deal regarding cleaning up of the current system and working together. Unfortunately, egos on both sides and PML(N) losing favor of the boots wouldn’t let this happen. PML(N) is still better than PPP in that they are corrupt, but they invest the looted money in the country, at least creating jobs. I feel they are a little bit more concerned about national interest in major decision making than PPP as well.
PPP … RIP, Pakistan? A ‘democratic’ party that appoints its chairman based on will of a deceased person. Treats Pakistan’s assets as ‘Family and Friends’ package from mobilink. Epitome of corruption and nepotism.
MQM… google, "MQM returns to government’ and LOL. Rental mercenaries, recently used well by Rehman Malik (almashor daktar peace).
Allegations on Imran:
Establishment support: There is some evidence of that and I am willing to assume he does. But then, Zardari currently enjoys it, NS had it for years and their performance is for all to see. Nawaz Sharif had establishment support + 2/3 majority and he still felt insecure and would try to kill any opposition.
Corruption: Misusing public funds designated for SKMT Hospital for his political purposes? Ah, well, better than or at least equal to rental power projects of financing sugar mills with public money.
Inexperienced political team: We did allow Benazir to rule us when she had hardly lived in the country for substantial period of time. More ‘experienced’ politician generally means he/she knows more loopholes and ways to generate personal wealth and power.
Liar and hypocrite: Lets assume he is. Find me an honest politician. Those in PML or PPP and keep quiet on what their leaders do are equally responsible.
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The idea is that whatever you claim he is, he cannot be worse than the current lot. Worst case: he is as corrupt as the current crop of ‘leaders’, which makes no difference if I vote for him or another guy.
I don’t think he can ‘win’ elections any time soon. I don’t even expect him to accomplish whatever he claims he would do if miraculously he does come into power. I at least believe he would show a little more sympathy than our current leaders while raping my country.