This is a feedback from users in Taiwanese government agencies. "Repeat" action is a convenient one, but users would usually use mouse in their right hand and press the combination keys with their left hand. When using an EN keyboard (QWERTY) which is used in Taiwan too, the Y key is far from Ctrl and Shift keys. It's even easier to press Ctrl+Y than Ctrl+Shift+Y because when we want to redo we can use our palm side to press Ctrl and index finger to Y; Ctrl+Shift+Y is more difficult. I've discussed with our lecturers and tried to find some solution. The default shortcut of Repeat in Microsoft Office is F4, which has been taken in Calc (Cycle Cell Reference Types) and Impress/Draw (Position and Size). One solution is to make the "Repeat" action added into the context menu. However, from the "View" - "Toolbar" - "Customize" - "Context Menus" - "Target" we can see really a lot items. It's difficult to teach users how to add the "Repeat" action into the context menu. IMO It is a user experience issue. One solution is to make it into the default context menu in every target, which I think it makes sense. Just that as Heiko said in our discussion, context menu has been too heavy loaded.
Typically, Undo is ctrl+z so we have ctrl+y or ctrl+shift+z for Redo. Repeat is similar and therefore accessed per ctrl+shift+y. Introducing some arbitrary shortcut would be hard to learn.
The 'Repeat' action is a weird construct anyhow applying only to the last action--and immediately removed once another action occurs. Not to be confused with Undo/Redo stack. But it is convenient for use with a Mouse where cursor movement does not clobber the prior action. While keybaord movement usually will (repositioning for mix of accelerator, <alt>+E, R [or as localized]). So issue is one of ergonomics for mouse users. The <Ctr>+<Shift>+Y shortcut is difficult one handed. While getting customization of the correct context menu is beyond most basic users. A 'two-finger' <alt>+y might be a more suitable one handed Shortcut for mouse users?
Context menu was suggested in bug 108859. A two-hand shortcut is the disadvantage for some languages. There are many other bugs where non-english languages have problematic shortcuts for users. This is the other way round. It seems, MSO has the same shortcut for redo an undone action and repeat an action. https://support.office.com/en-us/article/undo-redo-or-repeat-an-action-84bdb9bc-4e23-4f06-ba78-f7b893eb2d28 If any other combination is favored, Y should remain a part of it.
From the design meeting: + I always use TWO hands for that keyboard shortcuts =) (Roman) + keyboard issue for English, see also bug 115052 for other than English + Excel (or all MSO) uses F4 (or ctrl+Y) for "repeat last action" (but the same key also for redo) + shift+ctrl+r? - cannot press it without hurting myself, ctrl+alt+r works + alt+<key> should be reserved for hotkeys + keep it - common, usable (maybe not for everyone), consistent (Heiko) + more opinions needed (Roman) => keep it boiling for a week
No further input so let's close as WF. There is no good solution for all keyboard layouts. Localization teams have to provide good default shortcuts and users can customize to their liking.