One of the goals should be reducing the frequency of keyboard <-> mouse switches. If I'm using Paint, it would be annoying to type to search for commands; it would be the only time I had to let go of the mouse. It works the other way, too, and such "keyboard-centric" applications will benefit from a fast and easy command search.
And no matter what, as many commands as possible should have a keyboard shortcut, which should be listed next to the command when you search for it (this doesn't look to be the case). When we already know which command we want, we don't need to search for it.
I understand the need to force a shift to new/better features, but that doesn't mean removing features for existing and continuing use cases.
I'm curious why Canonical thinks it's a good idea to train users to rely on the keyboard to find things. (Ever tried to find a program in Dash?) Despite the rise of the "search" paradigm, keyboard shortcuts, and typing in general, have always been the domain of experienced users and programmers. Ordinary users tend to rely much more on the mouse; they type only when absolutely necessary. In fact, unless the new interface gives them plenty of hints, they'll probably no idea what to type. Wasn't Ubuntu trying to make things easier for ordinary users, even at the expense of power users? Or does the benefit outweigh the potential disadvantages in this case?