First - I just deleted my Google+ account last week; aside from too few of the people I know being on there, Google doesn't seem to be developing it -- no new stuff coming along, and nowhere as much there as FB.
Nice rant... You seem to be out of sync with me -- I wasn't being directed to a sign-on page after logging out a few weeks ago, but it was fixed for me last week. I know what you are saying tho, they keep playing around with that stuff. I think it is their Marketing department telling them to emphasize something; like You+, which I had not noticed until you mentioned it.
I'm a big fan of Firefox, mostly because of its customizability; my v12 looks like v3.6 because of the Status-4-Evar plugin doing what's not built-in, and Winstripe Toolbar Icons gives me the old colored icons like in v3 instead of the dull gray stuff.
For your black bar problem:
Two plugins I cannot live without are Nuke Anything Enhanced (right-click an object and select 'remove this object', and it is gone for that view of the page) and Customize Your Web. The latter is useful for permanently doing what the former does. The first nuke on Google's black bar gets rid of the black, the second gets rid of the text [bar] and everything shifts up. Customize Your Web can be a little iffy with some things, and it helps to modify the URL to make it more generic before saving the script (double-click the URL Pattern and modify it to be http://www.huffingtonpost/* to make it global instead of for just that page).
I have found that IE Tab is mandatory; I still run into pages that will not work right on Firefox. But every time Mozilla does something that makes me want to dump FF, someone makes a plugin to fix things for me. With AdBlock and the Nuke/Customize plugins, my web pages show me just the data. No ads on a Google search pages, no ticker bars of tweets from twits, no TechRepublic black bar (that does hide text, Google's doesn't for me). If there's too much crap on the page to manually hid, I just use Clearly or Readability, or I use Firefox's View>Page Style, No Style to disable the CSS, and the real data is grouped together in a block in the middle of the viewport.
Yeah, there is some level of work involved, but I get great satisfaction in defeating their stupid marketing antics.