Hi @jw,
There's no problem deleting the deprecated licenses and adding their SPDX identifiers to the new licenses. When you delete a license, it will remove the association with packages.
However, the compliance analysis scheduled job will reassociate them. This runs nightly, or you can manually run it. Also, if you visit the package page or download the package, it should associate with the new license.
We'll definitely reconsider the design/approach if there's more demand, but we need to really make sure there's a value to the user -- there's a relatively high cost to change things and then there's a chance of regression/bugs, which is really frustrating to users.
-- Dean