In any number of posts, I warned that, based on past precedent, Presidents almost never roll back executive power, even if they promised to do so in the election campaign. For example, I wrote on innauguration day this year:
...thoughtful people already on day 1 should have evidence that things are the same as they ever were, just with better PR. For God sakes, as his first expenditure of political capital, Obama is pushing for a trillion dollar government spending bill that is basically one big pork-fest that might make even Ted Stevens blush, a hodge-podge of every wish-list of leftish lobbyists that has been building up for eight years. I will be suitably thrilled if the Obama administration renounces some of the creeping executive power grabs of the last 16 years, but he has been oddly silent about this. It seems that creeping executive power is a lot more worrisome when someone else is in power.
My own hunch is that presidents try to keep campaign promises that expand the government and their own power, and either back down from or are unwilling to expend much capital on promises that make government smaller and more accountable, thus limiting their own power.
Looking over PolitiFact's report card on Obama's campaign promises, that seems to be about right thus far. By my count (and some of this is certainly subjective) of the of the 31 promises the site says Obama has kept thus far, 20 in some way grow or expand the federal government. Just six make the government smaller, more transparent, or more accountable. The remaining five have no effect, or amount to a wash.
Of the six campaign promises PolitiFact says Obama has unquestionably broken, five would have limited his own power, provided tax breaks, or provided more accountability and transparency to the federal government. One was mostly symbolic (recognizing the Armenian genocide). So far, he hasn't broken a single promise that would grow or expand the government, though he has compromised on a few, and many have been stalled.