true story.. David Hasselhoff..

Nah, Hasselhoff just did East Germany.

Total failure of communist economy and sclerotization of government already brought it to the brink of the precipice, then Afghan invasion military and economic disaster, Ronald Reagan "star wars" bluff, making USSR believe USA were far more ahead than where they really were (their first very partial missile defence weapons and tech became partially effective only in the '90s, and back then just against Saddam's very simple missiles) pushed them to furtherly increase their military expenses that already were the highest in the world and maybe beaten in ratio to GDP only by North Korea, then it had a smaller but still important role also the election of Pope John Paul II, a Polish, that helped Solidarnosc to open the first cracks in Poland, the third Warsaw Pact country and the first partially successful after the failed attempts in Hungary and Czechoslovakia many years before, add that the increasing role of communications in world economy furtherly pushed back closed regimes, sum all this, many other factors I don't know or forgot or even still unknown and the catastrophe was unavoidable. Gorbachev tried to save the system making it more human to make people that by then could not stand it anymore still accept it again, but he failed.

The inability of the Soviet Union to stamp out ethnic identity (or at least melt it away like we largely have in America, where a White American would primarily identify himself as such, as opposed to a Soviet citizen who was very much still a Russian, Kazakh, Lithuanian, Ossetian, etc) played a part, since the country was relatively easy to divide along ethnic fault lines

Yes, true this too, and despite being formally a federation, USSR retained the strong centralism of the old Russian Empire, with a strong hegemony in the central administration of some Caucasian Ethnicities, adding to this that the annexation of some parts like the Baltic states was quite recent, there was just another strong ingredient to favour collapse and disintegration. The reason I listed before were just for the collapse, I overlooked the disintegration factor that was important too.

Russian isn't ethnicity. Your quote is like saying "furniture, chair, table, sofa". It's effectively was playing the same role as American in pre-Soviet era in this part of the world. But I understand the confusion, it's may seem like ethnicity after some 1200 years of history for a foreigner.

National policy is indeed the weakest point of Soviet internal policy in general (outside Iosif Vissarionovich, maybe), but for a completely different reason.

I liked the premise of Soviet Union, what I didn't like is what it turned out to be after years of dictator after dictator, and constant global squabbling between the west and the east.

I like Putin, he's a man with a vision, however he's going to have a hard time enforcing that vision in a good way, and there's always a chance that if he steps down then his predecessor will be of a different mind.

Hopefully this works out. It is always good to have a balance of power in the world.

Well they didn't even try, if anything their policy was the exact opposite.  Promote each groups own race and nationally and play them against the other races to insure they don't band together.

Your choice of verb there is the exact reason why Putin isn't good for the rest of the world at large PERIOD or Russia in the medium and long term.