It's pur speculation trying to assess what the impact of any President or elected official will have on the economy or capital markets. It may be fun and inteersting to debate that, but It can be outright dangerous basing investment decicions on such conjecture. Best of luck!
In simplest terms, yes. Romney's background in business in and of itself is a dramatic difference from the current administration. Secondly, the current adminstration has used the EPA to limit expansion of several industries(ie. Energy) and the Healthcare Bill to control businesses(ie. limiting compensation, expanding governmental powers, and increasing business' responsibility to provide benefits). This has all led to many companies who are sitting on record amounts of cash to do nothing until they "understand the rules of the game). This is a opinion, on my part, but I believe this is because the current adminstration puts a philosophical priority of the environment, "leveling the playing field", and punishing abusive companies above that of job creation, smaller government and self-governance. I believe the US economy will see a dramatic growth spurt if Romney is elected, but how the new administration handles the massive current challenges will be much more important. On the other hand, the US Supreme court could strike down "Obama-Care" at any time and business could sky-rocket immediately thereby increasing the chances of the President being re-elected! Wierd stuff.
At the margin, a Romney administration might be a little more pro-growth than an Obama administration, but probably not enough to matter all that much. Here are a couple points to consider:
The president of the United States has little power over the key issues driving the economy and capital markets today: the European sovereign debt crisis, the deleveraging of American households (i.e. Americans paying down their debts and saving for the future), the aging of American and European Baby Boomers, and the rise of emerging market powers like China, India, Brazil, and Turkey. The President, like King Canute of old, cannot control these macro trends any more than he can command the tides.
The republicans talk the talk about cutting the size of government, yet they refuse to touch the one piece of the government that is both discretionary and large enough to matter: the military. And not to unfairly criticize one party; the democrats appear to be slightly more in denial than the republicans about the sustainability of America's social liabilities (Social Security, Medicare, etc.). In other words, both parties split hairs about relatively unimportant issues while ignoring the proverbial elephants in the room.
Even if Romney embraces the small-state libertarianism of the Tea Party (which is doubtful), we won't enjoy the benefits for several years--perhaps long after Romney's term has ended. In the short-term, we could expect a dearth of demand as the federal government's role in the economy shrinks.
A Romney administration would likely maintain the Bush tax cuts more extensively, which would certainly be a boost.
There is always a period of regulatory uncertainty when a new president takes office, but I would not expect something too terribly destabilizing from either candidate. A second-term Obama would not try something as ambitious as another project the size and scope of ObamaCare, and neither would Romney.
In the end, it is American companies and entrepreneurs that boost productivity and push the economy forward, not the man in the White House.