There are a lot of criticisms about perestroika and how it impacted the Russian economy and led to the fall of the Soviet Union. But I honestly can't imagine it going any other way. I think that the Russian society was so tired of the Soviet system, that reform and change became absolutely necessary.
I read that one of the major problems of the Soviet government was the fact that government employees were incredibly old, I think the average age was 70! Most people died while they still held their positions. This means that there was absolutely no innovation and little or no change in the way things were run.
And from what I read about the economy of the Soviet Union, it was pretty bad even before perestroika. Not only did the Soviets have to spend huge amounts of money for defense due to the Cold War with the U.S., but there was also a large black market and corruption that was eating away at the economy.
I don't think that perestroika is responsible for the bad Russian economy nor the fall of the Soviet Union. It coincided with these events, but I don't think that it caused it.