Brezhnev dying prematurely would also have interesting side effects in the space program. Mishin is still the head of OKB-1 and Glushko doesn't yet have total control over the Soviet program, for good or ill. If (a big if) there is an anti-Brezhnev turn afterwards, you might even see Chelomey return from the dead, as it were, and become again a third leader in the space field, especially if Blackfox is correct and Minister Grechko becomes the General Secretary, as Chelomey was supported by him.
What that might do, since Mishin and by extension OKB-1 and their associated manufacturing plants is unlikely to be enormously more competent than IOTL and Glushko isn't going to be calling the shots after absorbing OKB-1, is basically kill Soyuz and Salyut in favor of the TKS and Almaz, at least in the longer run (in the shorter run, the Soyuz will probably still be used). In practice, this wouldn't make a huge amount of difference in the design of Soviet and Russian space stations, but it would be interesting.