Actually you are not putting the record straight and speaking half the truth instead of full. Americans never had 'good' relations with any of the Pakistani government, and sanctions after sanctions are a testimony of their disagreements with Pakistan on several issues. Now Aslam Baig was not the only one, Gen Janjua, Gen Kakar, and Gen Kiyani also had the chance to topple the respective incompetent and corrupt governments and take over but they did not do that. Imran has tons of weaknesses but at-least he is not corrupt and even after throwing every possible resources into investigation, neither PPP nor PML(N) could find anything about him.
And that is why he has been a staunch supporter of Taliban? the same Taliban who are responsible for the murder of 50,000+ Pakistanis.
Your argument sounds extremely oblivious of political history and circumstantial dynamics which cannot be expected from a dogmatic supporter of ANY politician in Pakistan. ONE has to take the scales of dogmatic blindness off the eyes, and brain for that matter, to realize the historical realities. The so called politically conscious Pakistanis have always shown dearth of historical knowledge and have tried their utmost to match one thing with another without even bothering to put the intrinsic realities together that remained the undercurrents of the then prevalent circumstances. Lets see the situation of all the Generals that you have mentioned to counter my argument: (and I strongly suggest that you put all the global and domestic reports in front of you that were reported on these Generals)
Janjua: He was one of the most conspiratorial general in Pakistan's recent history. While running the operation against MQM in Karachi, he was also hatching a conspiracy against Nawaz Sharif government and had instructed ISI/Military Intelligence to push for the long march under the leadership of Benazir and other so called hypocrite forces. He DID not have good relationship with Ghulam Ishaq Khan because he had destroyed the influence of Irfanullah Marwat in Karachi who happened to be the son in law of then president.
HE HAD ALL THE PLANS to take over but his dream to realize the plan came to an abrupt end when he suddenly died of heart attack during morning jog - the cause of death was excessive amount of Arsenic in his bloodstream and the so-called long march organizers tried to put blame on Nawaz Sharif but all the courts cleared him. So, he was not alive to cherish his goals when the opportunity presented itself, hence there is no question of him being not interested in taking over!
General Kakar: Wow; I never expected that someone claiming to be putting the real honest record in light doesn't know the doings of Kakar. Its is the mindset of "I-know-the-ultimate-truth" that has destroyed the honest reality-check of our country's circumstances. Just to refresh, General Kakar was the personal choice of Ghulam Ishaq Khan because he wanted a General who would clip the wings of Nawaz Sharif and would continue to materialize the plans of Asif Nawaz Janjua, of which Ghulam Ishaq Khan was very much part of - though he didn't like Janjua was his hatred towards Nawaz Sharif was more than his disliking of Janjua - enemy of my enemy is my friend!. It was FIRST time in the history of Pakistan Army that someone from Supply Core was made head of the Army - even otherwise a stupid choice. If you recall, Ghulam Ishaq had dissolved the national assembly and dismissed Nawaz Sharif government; and Kakar had agreed with Ghulam Ishaq Khan on that dissolution. But Supreme Court declared the dissolution unconstitutional and reinstalled Nawaz Sharif as a constitutional prime minister of the country. Ghulam Ishaq was not happy with Supreme Court, and was confident that Kakar will support him in hatching further conspiracies. Later, Kakar did interfere and threatened Nawaz Sharif with dire consequences if he wouldn't resign, so the later had to resign. Just to let you know that later Ghulam Ishaq Khan immediately appointed Asif Zardari as the Defence Minister of Pakistan in the interim government and Kakar did attend the oath taking ceremony!
Kayani: Kiyani was never in a position to take over even if he ever wanted to. He was appointed as a consensus Army Chief in the presence of Joe Biden (current US V.P.), General Musharraf and Benazir Bhutto, when NRO deal was being mediated by USA between Musharraf and Benazir. Its part of the history books now that Kiani was present in the meeting; and when the question of next Army Chief came up for discussion, Benazir immediately pointed to Kiyani saying that who could be a better choice than him; the reason being that Kiyani was Benazir's Military secretary when she was prime minister, and Musharraf also like him. And for everyone's information, Kiyani was very much present in that infamous meeting when Justice Iftikhar was asked to resign by Musharraf and he declined to follow the command; Kiyani DID push Iftikhar to comply! So, it was CIA, US Administration, and OTHERS who had guaranteed that Kiyani would not take over. So, this angel is also dead!
By putting forth above clarifications, I don't mean that Aslam Baig is an angelic person, rather he has his own issues that don't need to be discussed under the ambit of this matter. However, he was best placed to take over in 1987 when Zia died. After his death, there was no Government at all: Prime Minister had been dismissed, assembly had been dissolved, President had died. So, the ONLY powerful person left was the Army Chief who could have easily taken the charge and he would not have been called a usurper because he would do it to fill the power vacuum. But he didn't do it, and let the then Chairman of Senate take oath as president of the country, who happened to be the old vulture Ghulam Ishaq Khan, that was the absolute constitutional path he took, and there was NO ONE WHATSOEVER who could have stopped him.
Rest is history. And please remember, I say such things because I LOVE
ONLY PAKISTAN, and any politician, any whatsoever, CANNOT be superior than the good of my country......and I see that Imran Khan is the worst thing that has happened to Pakistan. You might have different opinion, but please love your country first and then wash every politician's linen with detergent of history......and you will see the difference! Devils are always in details.