It isn't the capping of the MID that is going to affect most people, it's the "relabeling" of the personal exemption as a part of the "standard deduction".  When considered together, the total of the personal exemptions and standard deduction is not changing all that much, but mortgage interest will have to meet a much higher hurdle before any tax benefit is realized.  Only the mortgage interest that exceeds the new standard deduction will result in a reduction of taxes vs. a taxpayer who doesn't itemize.