Remaining as governor would have made it impossible for her to run. The number of warrantless lawsuits aimed at keeping her tied up by the liberal machine kept her from taking care of Alaska, tied up her time, and prevented her from raising the capital necessary to make a decent run for president. She has actually positioned herself well for a run if the will of her supporters are behind her.
McCain, Obama, Biden, and Hillary set aside their duties as Senator's to make a run. Governors in Alaska don't have that luxury. Her move to resign did two things. It freed up the governorship to get on with the important business of governing Alaska and allowed Sarah to organize for conservatives who are sick and tired of moderates in GOP clothing.
Push the moderates out and see where it gets the GOP. Fact is, the GOP was hijacked by these so called conservatives. When in reality, the conservative that Sarah Palin can legitimately claim is social. Sure, she is pro life. Yep, she is against gay marriage. Does she want to revive the spirit of the true American. You betcha. Conservative? Other than wanting to spend an ass load of taxpayer money on a bridge in Alaska, then only canceling the project when it became clear that Alaskans would have to pay for their own damn bridge, she a pretty decent track record. My problem is her preparedness. A Vice Presidential candidate that cannot accurately describe the duties of the Vice President is a problem. A political candidate that will not let go of a tactic that isn't working is a problem(ie. Bill Ayers). The sense that she is incapable for abstract thought is a problem.
Politics aside, the right needs better spokesperson. The binding glue of the GOP is conservatism, whether it be political or social. When the social conservatives figure out that the people that they label as moderates or RINO's are actually more conservative than they are on political issues and are willing to overlook the rabid obsession that they have on issues like abortion and homos, then the Party will actually come together. Instead of these social conservatives screaming for what they call moderates to shut up and get out of their party, I would like to see these "moderates" take their party back. Without liberals like Lincoln and Teddy Roosevelt, and true conservatives like Goldwater, you social conservatives wouldn't have the platform that you do. Grow up. Figure out that you are not the whole GOP and get used to the idea that even Reagan was more moderate than you. Otherwise, be prepared to spend a lot of years as the opposition.