Office documents workbook
When you create a new workbook, there could be an option to create an 'Office documents' workbook. Then, when you add a new worksheet you would have the option to create non Excel types of worksheet, e.g. a Word document, a PowerPoint slide.
Ideally these would be linked, so the Word document could link to data on the Excel worksheets. This is already possible (e.g. you can embed an Excel extract into a Word document), but has the problem of the Excel file being stored in a separate location to the Word file. Having all the information stored in a single file would be a benefit.
The Word, PowerPoint worksheets could have the full capability of Word, PowerPoint for users with Office. If you only have Excel, then you could have limited versions of Word, PowerPoint.
I sent all my excel files to documents but I can't find them
I too have been wanting this for a long time! It seems it would be easy enough for them to implement since Excel already has sheets and programmers could easily add an option to excel to insert a new sheet as a word document. Embedding word documents in excel or excel into word documents has so many glitches. I can't believe this idea was shared 2.5 years ago and has not gotten more tread! Please consider this Microsoft! It would make things so much easier for users who need both Excel & Word, etc.
Scott Sobel commented
Gary, thanks for pointing this suggestion out to me. Yes, this is exactly the same idea I had, so I hope the ideas and votes can get consolidated. This would be an incredible boost to real-world productivity. Heck, it might even boost GDP, this idea is that beneficial.
Brett Ables commented
I could see this working in OneNote which already attempts to fill this role, but doesn't handle embedding as well as it should.