Pataki did some good things early in his tenure. He strengthened criminal sentencing against tooth-and-nail opposition from the criminal coddling liberal Democrats in the State Assembly. He cut taxes, and toughened welfare requirements. I'd call his first term a pretty decent success.
After that, he sold out and became a Democrat-lite. It's interesting that Democrats are so critical of him, because he pretty much enacted the policies the Democrats wanted, while making a few noises occasionally in the other direction.
I think he lost interest in the job, and should never have run for a third term. New York politics is interesting in that New Yorkers seem to like their elected officials to serve a long time, even if they're not particularly popular or effective.
I think the most horrible person in New York politics is Sheldon Silver, and that Pataki could have been far more successful without this knee-jerk corrupt criminal coddling liberal in charge of the Assembly.
As far as his presidential run, it's obviously a joke. The only think I can think of is that he's really running for Vice President, as a prestigious way to cap off his career.
Pataki's problems (regarding popularity at least) started with the start of last term, well in actuallity during his campaign prior to it. Tried to paint the state fiscal picture as strong. Shortly after his re-election he suddenly did an about face on the state's fiscal shape. Suddenly we were in debt and couldn't pay for crap, promised increases in school funding were null & void, in fact tuition at school colleges went up (including my own) after he promised not to touch it. Overall school funding were well below promised levels, and cut in some cases. Schools needed the $$ from somewhere, the result increased propeerty taxes. Pataki pushed through a plan to cut taxes on top of that. Pataki also pushed through some tax cts which mainly benefitted the wealthy, the small amount that did slip down to the middle class was not even remotley close to the increase in property taxes that arose from the school funding cuts.
It was all downhill after that. his role in the Freedom Tower problems, as well as him taking a dash to the right over the past couple years hasn't exactly helped.