An interesting article in Haaretz on what Sharon was looking to do:
A series of cables from the U.S. Embassy in Tel Aviv to the State Department that were leaked to Wikileaks show that in fact, even before the Gaza withdrawal, Sharon was planning his next big diplomatic move. Moreover, leaked Palestinian documents show that after Yasser Arafat’s death in November 2004, and even more so once Mahmoud Abbas was elected Palestinian president the following January, Sharon made efforts to coordinate the Gaza withdrawal with the Palestinian Authority. …
In his summary of that meeting, then-U.S. Ambassador Dan Kurtzer makes it clear that Sharon had no intention of stopping with the Gaza withdrawal, but planned to take far-reaching steps in the West Bank and Jerusalem. Kurtzer noted that Sharon put emphasis on annexing the major settlement blocs, implying he would concede other parts of the West Bank, and that while he would not even discuss dividing Jerusalem, he would consider handing over some Arab neighborhoods, “but not the Temple Mount, Mount of Olives or the City of David.”
We’ll never know what would have happened if Sharon had lived, but I think we would be closer to a peace settlement. However I doubt we would have one, as both parties need to want peace, and while Fatah sort of do, Hamas do not.