The key design tension is whether the main space should be the asset you are working on or the work being delegated.

For a lot of tasks, I don’t think you will need to stay inside the document or app the whole time. But I can also imagine starting from an asset you already have open ie a PDF, spreadsheet, etc and bringing agents and tools into that context, rather than creating a separate task and attaching the asset again.

With that in mind, I agree that fanning out into disconnected task outputs is not enough. Sometimes the asset itself should become the center of the workspace, with the delegated work happening around it.