Okay, awesome. My use case is as follows.
I create a new folder for each new client/project I get. And I like to have Hazel watch each of those new folders to organise documents within those folders into subfolders (e.g. moving correspondence into a correspondence subfolder, moving receipts and invoices into a billing subfolder, moving draft documents into a drafts subfolder, etc). As the rules that sort the documents into subfolders are the same for each client/folder, I store them in an external file that is synced between each folder. When I create a new client folder, I add it to Hazel and specify that it is to sync with my client folder rules.
For each new client folder I also add a rule to my Downloads folder, which is monitored by Hazel and acts like my actions folder/inbox. The rule checks to see if a document contains the client/project reference in its name or contents and, if it does, moves the document into the corresponding client folder where it will be sorted into the relevant subfolder by the previously mentioned rules. Although given that I now have a number of these rules in my Downloads folder in Hazel, I don't actually add a new one each time; I just duplicate an existing one, change the client reference in the name of the rule and in each condition of the rule, and specify the new client folder in the move action.
So the workflow when I get a new client is to create a new folder in Finder, add it to Hazel, specify that it is to use the external rules sync file, enable the relevant rules, and then duplicate one of the Downloads folder rules and modify the client reference in its name and conditions. Currently I do this manually each time (like some kind of animal

) but it seems ripe for automation.
I'd love to create an AppleScript that I could run each time I have a new client to create the folder in Finder (easily done), add the newly created folder to Hazel, specify that the folder is to use a particular rules sync file, and create a new rule in my Downloads folder that would check files for the new client reference and move them to the newly created client folder.
I've also just encouraged a colleague to buy Hazel. She's not quite (meaning not at all) as nerdy as me but is keen for the productivity benefits of Hazel. I'll be able to get her set up with some of my Hazel rules, so she won't have to worry about trying to create them herself. I'm even thinking of just sharing some of my rules with her via Dropbox so that she can also have the benefit when I tweak/improve the rules, but just trying to work out a way to do this without sharing the rules that contain sensitive personal info like account numbers and stuff.
It would be great to have the AppleScript mentioned above for my colleague to use as well. She's the kind of person who loves things being organised, but doesn't quite have the diligence to consistently organise things herself. Which is why Hazel has so much promise for her. But after a while I suspect she'd stop taking the time to set up the new rules for each new client, and would thus stop experiencing the benefits of Hazel. But if the setup process was automated for her, she'd be much more likely to use it and would thus experience more benefits and would be more likely to continue to use/update Hazel.
So there's my use case and business case for you based on anicdata of one.

Thanks for considering to add AppleScript support and here's hoping you decide to go through with it. *fingers crossed*