Sure, any new UI modality will be at odds. But for mouse-oriented UI, I haven't seen anything better for a situation where you have many, yet infrequent, commands. A search interface seems like it could work well, but you'd have to know (a) that the software supported the command you're looking for, and (b) what aliases the software supported for that command. The Windows start menu search kinda works, most of the time; but that's because you generally know whether or not you have a particular piece of software installed. But when you don't know 100% if the software actually has the feature, and you're looking for it...

So in the absence of an effective search, it seems clear that a list of commands, grouped into categories, is best for finding infrequent functionality - particularly when a mouse is the modality.

One thing I am absolutely certain of: searching for a command in a ribbon is harder than searching a menu. I've had opportunity to do both in unfamiliar UIs, and searching ribbons is definitely harder.