I would be fine with having a lower cap or eliminating the mortgage interest deduction.
I believe tax deductions and credits should be for the minimal non-luxury expenses required to produce income. You don’t tax a business on supplies or materials because those expenses are needed to produce revenue. You tax the business on the net income. Similarly I believe individuals shouldn’t be taxed on the minimal food, shelter, clothing, work transportation, health care, and education required to work a job and live a minimal life. But we should be taxed on all additional expenditures because those are not required to live and work, they are optional and purchased for pleasure.
An individual deducting $25,000 of mortgage interest has a luxury house, they don’t need that expensive of a house to work, they have it because it’s a luxury item they want. Just as having a $80,000 car is a luxury item, or eating a $60 dinner is a luxury item. Those expenses are not required to produce income and thus shouldn’t be deductible.
Why should the government subsidize the cost of housing? If you can’t deduct the cost of food from your income taxes why can you deduct housing? The mortgage deduction does keep real estate prices artificially higher, so that makes owning a home more expensive for some people.
Additionally, I would like the elimination of the capital gain exclusion on selling a primary residence. Instead a rule could allow something similar to the business section 1031 exchange, where you can roll over your basis into a similar property and defer tax impact.