Re: "The ribbon makes more features visible"
I'm convinced the ribbon is designed to punish those who predominantly use a keyboard. As an example, pre-ribbon to quickly accept an Outlook invite you'd press alt+c, the "c" being handily underlined in case you forget. Hitting enter sent the confirmation (or the arrows let you change the default behaviour).
In post-ribbon, I press alt (lo, the letters appear), then H (to select the "Meeting" tab, naturally the H is silent), then C, then E, S or D to edit, send, or don't send a response.
So from alt-C (with visual clue already there), enter. To alt <pause>, H, <pause>, C, <pause>, E, S, D. Thanks MS, it's now quicker for me to move off the keyboard and use the mouse.