Indeed. I have trouble understanding the logic behind the excuse "Well, Kerry's wife didn't release enough of her tax returns either!"
Number one, Kerry's wife was not running for public office; it's one thing to expect transparency in our public officials, but Mrs. Kerry was technically a private citizen, and her husband was not running on the platform that his wife's money would help him run the country. In contrast, Romney IS running for public office, and IS running more or less on the idea that his ability to make money will help him run the country. His tax returns are therefore germane to the discussion in a way that Mrs. Kerry's are not. Number two, the vast majority of candidates have followed Romney's own father's example and have released a sufficient amount of their tax returns in order to provide transparency in the last several decades; I am not personally aware of anyone aside from Romney (when considering people running for public office, incidentally, not their spouses) who has categorically refused to do so in the face of overwhelming calls to do so. I see in the article Joe cites another group claiming that Romney gave McCain 23 years worth of tax returns; while I don't know if that number is accurate, it seems fairly clear that Romney has had no problem releasing such things in the past, albeit in circumstances that would keep them out of the public eye. What has changed now? His primary opponent has released, in total, eleven years worth (the seven years released while running for the Presidency and every year in office since), and those tax returns provided an excellent overview of the President's fiscal life leading up to office.
The way Romney keeps dithering on, I can't help but feel that little notion that he's trying to hide something grow more and more strong as time passes.