Who are you targeting as the main user of this software? Most users do not depend on keyboard shortcuts but rather repeatable actions they can use the mouse for. The ribbon only annoys power users which is a number much much smaller than 50% of all users. Plus keyboard shortcuts still exist with the ribbon system.
As someone who has spent a lot of time with “regular users”, no body is complaining about the ribbon…
You seem to have omitted a word.
> Plus keyboard shortcuts still exist with the ribbon system.
So this objection is completely manufactured?
> The ribbon only annoys power users which is a number much much smaller than 50% of all users.
It's 0% of the users who are new to the software, and 90% of the users who have used the software for some time. The UI shouldn't be optimized for people who are only going to use the software a few times unless the software is only meant to be used a few times.
But in the case of office software, what you want is affordances that can be eliminated at the user's own pace while they get to know the software over years or decades. Things like indicating the keyboard shortcut next to the menu entry, which is standard for most UI toolkits. Or things like allowing the "ribbon" to be disabled, which I would be really surprised if you could come up with a reasonable opposition to.
Edit: Maybe this depends on settings rather than versions? Upon further investigation, I've found some screenshots of Word/PowerPoint 2016 that have a search bar and some that don't.