"And, like you said, changing one parameter (like the number of generations one at a time) and having to wait to re-gen the entire report is just silly."
A little time can be saved on this [above] example:
After you have changed the generation by one let it start generating and then click cancel and change the next generation and again click cancel before it has a chance to run, etc, etc. If you wait a long time before clicking cancel it won't stop but will continue running and if you have a very large report that may take forever
The above is a very stupid workaround but it does work
The real solution is to change the software so that it doesn't start generating a report or graph until the user tells it to start generating. In other words let the user set all the parametes they desire and then when they are done/satisfied with the parameters they have set, then click on "generate "