I disagree. Romney has nothing to gain at this point by releasing more tax returns. Poor people file 50 page tax returns. Romney's are probably 600 pages each. Romney would be handing Obama and a media, that is already against him, nothing but ammunition to distract his message. His message might be simplistic but it is the most effective tool that he has and that is that the economy sucks and Obama's policies have failed. Most independent voters can get behind this over releasing a tax return. Maybe not all, especially independents that tend to lean left, but that is the calculated risk that Romney has to make.
When Obama released his returns, I spent all of five minutes looking at them and was bored. I can guarantee you I spent five more minutes than 99% of the voting population spent looking at those returns and the same percentages would hold true for people actually interested in seeing Romney's returns.
No one has bothered to read the returns Romney has released. Instead they focus on his rate and foreign bank accounts. As if Romney did anything wrong by taking advantage of the loop holes congress, but republican and democrats, have passed.
Making the populist stand sounds good. But if released his records as you suggest, there would be nothing but 4 months of Romney's tax rates, money overseas and other 30 second clips that really don't matter one bit.
Most undecided voters are undecided because they are capable of weighing evidence. It has been my experience that "unnamed sources" and my "friend" on the inside is not highly persuasive when trying to persuade an individual with a scintilla of intelligence. The only people who really care about this story are people who have already made up their mind who they are voting for.
Romney needs to stay focused on the economy, the unemployment rate, food stamps, the unpopularity of Obamacare and his success in business and the Olympics. If he wins, it will rest on this.