Regression: Workflow Create Entity Task failure after migration

There are two problems associated with changes made between 5.4.0 and 6.0.0 to the Create Entity Task workflow method:

The first is that in a migrated system you cannot edit a Workflow task if it used the Assigned To field in version 5.4.0 as the value for the entity to be created.

The second is that (IMHO) this is a serious regression. It makes perfect sense to be able to create a new Entity from a workflow that will be have its Assigned To value set to the same owner as the triggering record. This was possible in version 5.4.0 but is no longer possible in version 6 (on in On-Demand too).