Best practices (or patterns) for dynamically displaying reusable components

Hello all, the subject may not be a good summary of what I'm looking for, so here's a bit more context for this posting.

I need to create a set of user interfaces, each of which serves a specific purpose in an application. But a lot of these UIs share similar functionalities (e.g., Approve/Reject decision, Doc upload, Confirmation, etc.) that I'd like to turn into reusable "parts" that will become part of a parent "wrapper" interface object. So, the idea is to always use the parent UI object--this holds common elements such as a page title--and pass in an ID as a rule input, which will be used to determine which of the reusable parts will be displayed within the parent UI.

During my online search on this topic, I found this Community posting and this blog entry by [mention:a11f77a729fb4db2af76b09948583328:e9ed411860ed4f2ba0265705b8793d05] to be somewhat relevant to my needs. But it seems that Appian at some point started preventing users from storing rule/function references in local variables, which would have been a useful feature to have.

I get the sense that I'll probably end up using the a!match() to determine which of the reusable components to display but I'd like to think there's a better/proper way than hard coding a LARGE block of a!match() that contains all of the reusable UI components, all in one object. Any pointers/tips/guidance will be much appreciated!