Romney didn’t release his til september and reid said even then romeny only released a summary and not his actual tax return. I don’t think it be breaking any rule by releasing it after the nomination
Financial disclosure forms are important, because they reveal any potential conflicts of interest.
Trump did that. In fact, all the candidates did that, as it is required by FEC regulations.
Of course, Cruz lied on his, failing to disclose sweetheart loans from Citibank and Goldman Sachs.