While the standard grids still lack some quick totals functionality (count, sum, average) and users have to export to Excel just for that:

It would anyway be great to make the experience of opening the data right in Excel as quick as possible, with as few clicks as possible.

Please consider enabling the following optional default behaviour: when exporting to/opening in Excel, it should open the data in Excel Online in a separate tab (preferably in Edit mode).

It should also be available as a direct keyboard shortcut form the grid (keep any active filtering). Ideally, it should work like Crtl+T in AX 2012 with an Excel Desktop window being opened immediately without having to first save the file etc.