Oh, nice! Thanks for the link, that's a really cool concept.
After a bit of hunting around, I'd been thinking the same way as the blogger you linked to - that writing (or templating) an XML file and importing that is much neater than using their Powershell for making rules. So I suspect that a lot of the work involved in making AppLocker hands-off way is really in figuring out all the UUIDs and SIDs and so on you need for a valid XML AppLocker ruleset.
Really, the main piece I'm missing is a way to import an applocker policy from a local file - there's already Ansible solutions for 'grab this file from remotely' or 'template this onto the target host with these parameters', and for 'manage the state of this service' (for AppIDSvc). I'll let the internet know how it goes.
Cheers,
Nikki