There is leaving something behind for your children (think a few millions) and then there are entire fortunes being passed down from generation to generation (speaking of billions here). Such huge amounts of money dont just trickle down because the heirs are idiots. The money keeps being concentrated on the 0,01%, which obviously is a problem for the society in the long run.
That said, I would propose to not tax anything below a couple million dollars, and make exceptions when it comes to family businesses. Like, if the heirs pledge to keep the business running for another decade (keeping the jobs etc.) you could relieve them completely from the tax, but if the heirs wind up the business you could talk about an increased death tax.
I'm against a general death tax though, especially not a ridiculous 75%.