Consider deprecating old components API

**Problem**
When working with controllers, the error messages could be more descriptive.

**Suggestion**
Improve error handling and add detailed error messages.

**Context**
This would help with debugging and maintenance.

No files, tests, or entry points are named. Start by locating the controllers and the old components API references, then review how current errors are constructed. Done is not fully defined; the issue needs a decided deprecation scope and specified detailed error messages before implementation can begin.

Written by the indexing model from the issue text.