I do not know what the original author means, but if I may, can you please add a way to DEFINE new keyboard shortcuts to functions?

I am sick and tired of having to keep swapping between keyboard and mouse (that's a rant about the trend, not your product specifically).
I am a strong believer that every functionality should be accessible WITHOUT a mouse.

Example: Merging cells, Ctrl+Shift+M (or whatever) or at least make it accessible from the context menu ("context" key)

Thank you for your suggestion! Just to confirm — Ctrl+E (center alignment) and Ctrl+R (right alignment) are already supported in ONLYOFFICE editors.
Could you clarify what you'd like Ctrl+D to do? In MS Word, Ctrl+D opens the Font dialog — is that the behavior you have in mind? Any details would help us evaluate this properly!

It is important to me