I don't expect Putin to have good takes on the USSR, despite how every liberal is convinced he WaNtS ThE SoVieT UnIoN BaCk.

But still, if you don't send troops to quash the revolt in Hungary, what do you think happens when the West sees that Eastern Bloc countries can be shaken with color revolutions? It became apparent in the 1980s, with the USSR in a much weaker position, that the Baltics and Poland were especially vulnerable. I don't know too much about the Prague thing, maybe someone can give some info.