Absolutely, it would be more efficient and effective. Just look at the way things are today. We have Democrats controlling the White House and sort of controlling the Senate. We have Republicans controlling the House. So nothing gets done as our problems get worse. A single branch with one party in power would obviously be able to get its agenda enacted without problems.
Now, the real question is, do we want to have a government that is more efficient or do we want one where it is harder to get anything done so that A) the government can't tyrannize us and B) hopefully policies that pass are better thought-out because they had to go through a harder process to get passed?