I could see Jeb being the most formidable GOP candidate in 2016. It makes sense, if he wants it. I expect to see Hillary, and unless Obama doesn't get an economic turnaround, she will be very tough to beat. Many felt that Obama delayed what was hers, and thus, feel it is her due. The GOP has a creeping weakness that doesn't help Jeb, though. Every year there are less white men. It might take an election or two before they get their heads around that in a meaningful way. They might be facing an intractable issue in taking the White House.
Obama will get an economic turnaround. The question is who will be in the White House when it happens. The numbers have been pretty clear recently, especially home prices and housing starts. If Romney wins, he'll reap the benefits, just like Clinton did from 93-96. If the 92 turnaround had started one or two months earlier, then there's no way Bush gets defeated; instead it was all hail Bill. The economy is its own beast, and it operates at its own whims.