The problem with (1) is that a large amount of inheritance taxes are taxes on illiquid assets. So if you inherit a $10M business, the only way to pay your tax bill is to liquidate the business. Needless to say, it's bad for society if a business is shut down simply due to the death of a founder.
The way to resolve (1) is if the IRS allows you to pay taxes on in-kind receipts with in-kind payments. I.e., if you get a business that the IRS claims is worth $10M, and you owe $3M in taxes on it, you can pay your tax bill by handing the IRS $3M worth of shares.
(This would also fix a major problem that startup employees have, namely that if they quit their job, they need to exercise options and incur a huge tax bill. But they can't actually sell the shares to get money to pay the taxes. Not a problem if they can give the IRS some of their shares.)
The way to resolve (1) is if the IRS allows you to pay taxes on in-kind receipts with in-kind payments. I.e., if you get a business that the IRS claims is worth $10M, and you owe $3M in taxes on it, you can pay your tax bill by handing the IRS $3M worth of shares.
(This would also fix a major problem that startup employees have, namely that if they quit their job, they need to exercise options and incur a huge tax bill. But they can't actually sell the shares to get money to pay the taxes. Not a problem if they can give the IRS some of their shares.)