This is an intentional screw job on mid-upper class folks whose parents were the same, but have an early demise. If the parent passes on while the heir child is still working, he's going to get socked with a big income while he is at a high rate because of his own income. Of course, some children may decide to FIRE at that point.
I presume that the heir can pick and choose just when within that 10-year period to distribute the accounts?
The one thing I don't like - although maybe I am wrong in this presumption - is that this will kill the idea of a conduit IRA, which is a great way to continue to keep the bankruptcy-exemption attribute of an inherited IRA (i.e., a regular inherited IRA is now no longer bankruptcy-exempt). Everyone should keep in mind the ability to file for bankruptcy in case he runs into an inner-city bus, etc. (hopefully, the driverless car, with its being indemnified by the manufacturer, will be around so that folks don't have to worry about that possibility).