Have you asked yourself: do you actually know anything about user interface design? Google employs Ph.D.s by the dozen. Maybe you need to stop offering uninformed criticisms? Google doesn't do these things randomly or on a whim. These changes were debated, thought over by smart people, and then implemented. It's like Roger Ebert vs. the opinion of J. Random Moviegoer here.
I guess I'm not experienced enough in UI design to be allowed to express an opinion either (at least, according to you), but I'll share my opinion anyway: I don't like the multi-column G+ design either, because I find it tiresome to shift my attention back and forth between columns, and keep track of where I am in each column.
I also find G+ slow (even on my fast CPU) and cluttered. I find the text is too small and if I zoom it two levels (to make it large enough to easily read), the rightmost column partially renders under the Hangouts column.
Page up and page down don't work quite right a large fraction of the time (try it), and I hate it when web sites pin content (if I scroll, I want everything to scroll).
I miss the old Google when UI designs were simple, intuitive, uncluttered, and fast. They seem to be junking up all their UIs (including Gmail).