She cares more about saving the country than "to be in control". If you really followed Palin, you wouldn't be saying such. Running as an Independent (now), would not be in the best interests of defeating Obama. Everyone knows this.
I'm no Ross Perot fan. But Ross Perot had a pretty good chance to defeat both Bush and Clinton in 92 had he not flamed out and did the I'm in, I'm out, I'm in flip flop.
Even after that, he still got over 20% of the vote. A guy self destructs and still gets 20% of the vote.
The times are more ripe now than then for a third party. (I think they were more ripe in 2010) Sarah's ego is big enough to want this. I think she's more savvy than to pull a Perot. But I think she will believe 3rd party will be the way to go.
Avoids the blood letting and throat cutting of the primary process. She stands to become damaged goods if she goes through that process.
Allows her to control her candidacy and her "party". Allows her to be a free agent until the last possible moment. That means more money in her pocket for her future security. Allows her to be viewed as the savior candidate.
If this were a normal election cycle, I'd say you're right.