While tirelessly looking for a method to automatically uninstall Workflow Designer instances found on clients machines, I  stumbled upon this little gem:
 
C:\Program Files\Altiris\Workflow Designer\Uninstall.exe
 
Just add an /S at the end for a silent uninstall
 
I have it setup in a software delivery job to run on a collection that is built using 'All computers' - 'Authorized Designers'.  The latter is a manually updated collection for now since it a small and static (for the most part).  I could also wait for the Operating System Inventory to populate (tablename: Inv_AeX_OS_Add_Remove_Programs), since that contains the contents of Add/Remove Programs and just build a sql query based collection for that.  Which I will probably do in the near future.
 
Hope this article was helpful.  Short, sweet and to the point.
 
Thank you.