Totally understood. We call that approach the “attic” approach: Keep all data just in case you might need it in future. That’'s what people do with the stuff in their attic, and, as we all know, nobody ever goes to the attic to pull anything out of there. It all gets disposed of when you move house. 
The reason the OMOP CDM is succesfull is it’s focus on the use cases, making it slim and efficient. It supports use cases that people really have. For everything else - why would you bother creating a CDM?
Your concrete use cases:
- Carer details go into the PROVIDER table. Or is there anything missing?
- Nursing assessments can go into the OBSERVATION table. What kind of assessments do you have in mind?
- Residency: What do you mean? There is a location_id field for the address. Or what do you mean by residency?
- Employment: Not sure how this is data relevant to the clinical data of a patient. But you could store it in the OBSERVATION table.
Let us know.