Fujimori made several mistakes that led to his downfall. The first, and most important, was that his chief of secret police was unstable, and prone to committing unacceptable acts, such as a rural sterilization program and blackmail programs.
Another mistake was in not building populist support, but instead relying on the military and the police for support. After dismissing the unpopular and corrupt judiciary, he should have gone to lengths to involve the public in the creation of a popular and far more honest replacement.
His national parliament, as well, needed to be redesigned and supervised with a republican, all politics is local, concept in mind. As much as possible, the representatives should live with the people they represent.
He personally should never have been an issue. Even if he didn’t want to delegate power to his lieutenants, it should be believed by the public that they were initiating and executing policy independent of him. However, when things didn’t work, then he could have stepped up and assumed responsibility, which would make him the good guy.
Largess is peculiar in central and South America, and keeping the quantities up, and price of staple items low can mean a government stands or falls. Tortillas and beans and rice can make or break a government, where more important issues are ignored.
The chief of his secret police had to do things (like wearing hoods) to protect the identities of his men so they and their families wouldn't be murdered in their sleep. The re-emergence of the Shining Path will test whether Fujimori and his tactics were justified. My guess is, at some point, the people will rise up and demand he take back the reins of the country.