This is a major productivity killer for power users such as finance teams, and current UX does not help exit this state efficiently.

Calculation Performance of iterative what-if Data Tables is unnecessarily slow. The reasons seem to be (in priority sequence):
- each iteration is using single-threaded recalculation rather than multi-threaded
- the overhead for the whole table calculation looks larger than it should be
- the process starts with a recalc, then does each iteration, then ends with a recalc: the first recalc is unnecessary
- if the values to be used in one of the iterations are the same as the start values the recalc for that set of values could be skipped

Please return offline help like in Excel 2010 (for VBA and Excel)... It is enugh to have just basic offline help without totally up to date informations in 98% cases.
Thank you.

With high-end mice, having a higher poll rates greater than 200Hz will produce a lag - not fluid - while dragging the window

Please bring back MDI for Excel. SDI is really slow, and crashes when I run the apps I've developed over my career that rely on multiple workbooks loaded simultaneously. Or re release 2010 and just call it the version for the folks who rely on MDI and there are a lot of us!!!!!!

When Excel detects a range stored as text it gives a icon that you can click to convert the strings to numbers. This however is incredibly slow when applied to a range, it takes more than 1 sec per entry on my i5 windows machine. For a range of 1000+ this take unbearably long without opportunity to interrupt.

I wrote a VBA code that simply does a .value = .value and pastes the range back into the sheet. This is 100s of times faster that Excel's built in functionality. Please improve the built-in function's performance

When I look at my task manager, Excel is usually only using approximately 14% of my CPU. I work with huge spreadsheets that take a long time to calculate. Why doesn't Excel use my idle processor cores / threads?

Remove "Translate" from Excel, you are ruining keyboard shortcuts. I do not need help translating "2" to "2" -- at least make this an option.

I am not entirely sure how this would be preformed but I have seen examples of excel using the processing power of a GPU to massively decrease calculation times when working with functions that can take advantage of the parallel processing that the GPU is capable off.

You should be able to rearrange the order of the pinned Excel workbooks.

we cannot share files on network drives since your change to only allow sharing on One Drive. Not everyone in our company has One Drive. Additionally, your help articles to unshare files in Legacy mode, does not work. The Legacy share options are all greyed out. This is causing us to completely recreate spreadsheets we depend on between departments.

Excel usability could be improved significantly, by improving performance in the following scenarios:
1) Large file open / save processes should be multi-threaded, since new file format uses threadable compression.
2) UI responsiviness should be improved (but I think this applies to all XAML/UWP code apps). Excel 2007 with forms is still 3-5 times faster than new ui.
3) List views, could those use hashed lists and quicksort (yes, this would use more memory, but it would allow handling much larger lists and filters with 100 times faster than currently).

Excel 2003 and prior had a wonderful feature - they allowed a user to create multiple customized toolbars with custom icons picked from a selection library or created in an image editor.

Pity Microsoft did away with that feature and replaced it with the disaster that they call a ribbon. It is sub-optimal for a power user and takes up too much screen space on a laptop.

Bring back the multiple customizable toolbars and keep the Excel 2010 feature that allows you to export the customization to a file and import on another Excel 2010 installation.