One thing the theory seems to gloss over is that it assumes dishonesty of current and past presidents. If the president wielded no real power, wouldn't at least one of them have said something about it? Out of 44 men elected for their vision and mentality, not one was brave enough to break the cycle of lies? And why would some, like Teddy Roosevelt, stand up for a second term after a hiatus if they didn't have any real power to change policy?
There are better explanations for the continuity in policy and the differences between candidate-Obama and elect-Obama. One is that they base their viewpoints on different information. As president, Obama has to base policy on classified information, secret dealings made by predecessors and staff, corporate interests, and in general "the big picture". As a campaigner, he wasn't burdened by any of those and could provide an idealistic view. At least we have evidence that all of these exist.