I encountered the same issue with a report subscription where the developer created a separate dataset for each report parameter.  There were close to 2 dozen parameters.

Creating or editing any of the report subscriptions would take several minutes just to open.  It took just 3 of those queries to make it several minutes long.

So I ran a monitor to see which queries were taking the longest and wrote down the stored procedure name.  I used Idera's SQL Diagnostic manager for this but you can also use SQL Profiler.

With the longest running queries/stored procedures captured, I proceeded to optimize and thus return the creating/editing report subscription performance back to reasonable levels.