Hi, dual heritage relationship here, (not 'black' but 'brown' but I think probably getting about the same level of negativity).
What you experienced earlier, IMO, will not have changed all that much.
We've been in Germany 13 years, Berlin for the last 11, in a different city in Western Germany for the first two.
As someone living here, I don't think being treated poorly or passport checking has actually changed all that much in the last couple of years. There are certain areas we would avoid, but we were avoiding them before anyway.
For us, it really comes down to which part of Germany you are looking at. Berlin, okay (though there are parts of former East Berlin we would never go to. Particularly areas further away from the center, such as Kopenick, Marzahn or Weissensee)
Former East Germany, we tend to avoid, unless it is really close to Berlin. That is, Potsdam would be okay, Leipzig would okay as a day trip, but not okay to live there. More rural areas in the East, we avoid.
Former West Germany, basically okay. Though larger cities of course are better than smaller ones.
Does this help? Hope I didn't add to your worries!