I'd say they were only better than the Kulagin led teams of mid-1970s (which, ironically, was extremely strong on paper but in disarray). 1987 team also lost the WCs, and lost to Sweden in CC prelims. They did, however, play great at Rendez-vous '87.
Ultimately, despite a paper thin roster, performance wise I rank them low because of goaltending. Unlike previous teams (with Tretiak) this squad never had a goalie that could make 'key saves' in big games.
It wasn't Gretzky/Lemieux that beat them in 1987......it was Fuhr's ability to make that timely save while Mylnikov/Belosheikin couldn't.
Yes, they lost the WCs... without losing a game in the tourament (two ties in the medal round). Sure, they knew how the system worked, so they should have won also 'the right games', but anyway...
I don't think there are many Soviet teams in history that had as good top and 2nd forward lines as the 1987 squad. And it's not like the Soviets often had very good/consistent 3rd and/or 4th lines anyway - except in the late '70s/early '80s.
BTW, which Team Canada was better, the 1972 squad or the 1987 one? The 1972 team, after getting in shape and becoming more of a team, battled evenly with the Soviets and won the last 3 games on Team USSR's home-ice. The 1987 TC was better prepared, had more & bigger stars, and they were playing on their home-ice in a tournament called CANADA CUP, and yet they played 3 life and death games against supposedly sub-par Soviets and needed some last minute heroics and maybe favourable reffing. I just don't see the 1987 Soviets losing to the 1972 Team Canada, especially being up 3-1-1 after five games.
I think Belosheikin played quite well in the 2nd final - for starters, he kept his goal clean for 30 minutes and 7 seconds in the OT. Mylnikov did look bad on quite a few goals in games 1 and 3, no argument there. But, say, Tretiak wasn't very good in Moscow in 1972 either.