A slide presentation of the co-chair's draft report is
here. One of the tax reform options (number 2, see slide 26) says: "Limit mortgage deduction to exclude 2ndresidences, home equity loans, and mortgages over $500,000." This same slide also offers the $15K/30K standard deduction.
I think it would best if the standard deduction were lower than this. In my opinion, those not in poverty should be paying federal taxes, even if the rate is very low (5%). Setting a high standard deduction produces a huge constituency of voters with no stake in restraining government spending or in reducing tax rates. That's not good for the country. 47% of Americans pay no federal income taxes.