> I think changes around capital gains and loans against equities could use some adjustments.

At minimum, taking out a loan based on the current value of an asset should trigger immediate realization of capital gains/losses for at least those assets used as collateral. After all, the gains are already de facto being realized for the purpose of the loan.

Unfortunately, I'm not quite sure how to address the other side of things - that said loans often don't have to be repaid so long as the assets continue to gain. As such, the capital gains are actually being realized continuously by the loan, but I doubt it's feasible to properly handle that in tax law.

The easy thing to do is set a limit for how much and how long you can borrow against, tax the loans as income, or outlaw loans against investment instruments entirely.