With the addition of templates for formatting reports (YAY!), it would be great if we had a way to default the display of a report through a template. Currently, there is no way to get to the final format of a report that has runtime parameters through a template without running the report first, then selecting the template. Templates are easy to run reports through if all the needed parameters are already in the URL, but if you need those parameters entered when the report is run, you options are limited. I would suggest that the report editor include an option to default the output to a specified template, or if you include a template parameter in the url, it would fist ask for runtime parameters, and then run the report with the template and parameters.
I agree that it would be helpful to be able to define a runtime parameter after selecting a template. Generally reports I've created to work with a template will never make sense to run without the template. I want staff to be able to run the report, enter a value, and get the formatted output without further selections.