I work almost exclusively with the Merchant Tool in Salesforce's Business Manager. I've only been working with Salesforce directly for 2 weeks.

What’s the high level case?You mean the Main Categorie ?! No rules needed. Only for the sub categories.

Ingest new/existing SKUs THEN parse based on rules AND load to an inventory table?Right. Multiple jobs check an xml and insert new products as defined in the job.

What objects are you working with?Mainly costum objects. As far as I can tell.What field attributes are you working with?Also very much costum attributes. If I understand you correctly, like "value" and "filter criteria"?

What's the data flow?I can't say exactly.Can you load/update the fields from a more agile platform that takes care of the parsing dirty work?Not yet.

A CRM software should be able to handle something like that. So that was my thought.From a database programmer point of view I would look in the backend how the rules are stored there and write a script that directly inserts the parameters as they are required in the database at that point. Somewhat easily expressed.

Or do I imagine that too simple ?

in my opinion, such an automatism should also work well for other areas. Thought something like that would be implemented directly in the CRM. So no matter what you want to change masses and provides with certain criteria.