The Tax Foundation ran the estate tax in their taxes and growth model and found that repealing the estate tax could create over 100,000 jobs:
Furthermore, as Alan Cole writes:
The estate tax is one of the least effective means of raising revenue in the federal tax code... It produces little revenue - only about $18 billion per year. And it is a tax on capital formation, which is highly elastic with respect to tax.
Those who are interested in raising federal revenue from wealthy individuals in an effective manner should look to taxes that are more direct, more income-based, and easier to administer.
In the grand scheme of things, the estate tax really doesn't cause too much economic harm or raise all that much revenue. But it's a good example of a tax that progressives have historically pushed for on the basis of morals or fairness rather than good economic sense.