Comments & Documentation: Clearer instructions and links.
Validation: Script checks if sp_WhoIsActive is installed.
Output Columns: No spaces in @output_column_list to avoid runtime errors.
Error Handling: Use of IF OBJECT_ID to prevent script errors.
Formatting: Improved readability via indentation and sectioning.
CROSS APPLY: Use r.sql_handle instead of r.plan_handle for sys.dm_exec_sql_text, which is the correct parameter.