There are many (myself included) that consider him a good or even great politician. Sorry in advance, I'm moving right now and my books are packed away in boxes on a truck somewhere, so I'm going on memory right now. Feel free to source me if I'm off, or you disagree.

Gorbachev oversaw the most radical sociopolitical change in the USSR since Stalin's seizure of control and the subsequent industrial and political revolution that took place from the early 30s until war with Germany cut his reforms short. Despite a brief unsuccessful attempt at loosening social and political controls under Khrushchev, the Brezhnev years (sometimes referred to as the Brezhnev stagnation) firmly retrenched Soviet policy in its Stalinist roots where it would remain until 1984.

From the dizzying heights of superpower that dawned with the Soviet space age to the steady but inevitable economic and social stagnation throughout the 70s the entrenched political class stubbornly guarded their prerogatives and privileges while poor quality in manufacture and scarcity in agriculture became bywords for the planned economy which failed to even seriously address the burgeoning tech boom becoming evident in the US by the end of that decade.

In 1981 when Ronald Reagan was sworn in as President, the USSR was put firmly on notice that a new arms race based around high tech conventional arms (smart bombs, next generation fighter aircraft, etc.) and strategic arms (SDI or "star wars") was imminent. While the Soviet Union's conventional and strategic arsenals were the largest in the world, the US' spending would force an immensely costly reform to prevent obsolescence.

Thus the Soviet situation was beset by problems in every direction: a stagnant economy with seemingly perpetual harvest failures, an economic, strategic and ideological threat in the form of a revanchist belligerent USA, a growing unrest in the Eastern European satellites centered around the Polish Solidarity Movement (a group which wished to address and reform measurable ideological shortcomings of Communist rule rather than resist Soviet hegemony in the region - a goal which garnered support from domestic intellectuals and moderate politicians, and made it much more difficult for Moscow to address than it had in Hungary in '56 and somewhat less than Prague in '68), and a quagmire war in Afghanistan that showed no sign of abatement. Couple this situation with an aging class of political elites following Brezhnev's premiership, three of which perished in just over three years after being named Premier, and the Politburo had little choice to make a dramatic move.

Four hours following Chernenko's death (so fast as to be unheard of in Soviet History), Gorbachev was sworn in by the Politburo. Owing much of his rise to the influence of Mikhail Suslov the reigning intellectual heavyweight of Marxist-Leninist thought and policy, Gorbachev seemed to possess the required talents to right the ship: good party record and connections, graduate of the prestigious Moscow State University, economic experience at the head of the Soviet Agricultural directorate (despite the fact every harvest he oversaw was a failure), and - perhaps most importantly of all - a member of the new generation rather than the aging Old Guard.

Gorbachev saw the only rout forward in three goals: the kick start of the economy in general and agriculture in particular, a social and political "buy in" of the populace that didn't remember either the Revolution or the German invasion (as well as those citizens if the satellite countries) that might revive some of the party's dynamism of the past instead of the contemporary antipathy toward the regime, and the end of the Afghan conflict.

The last goal was relatively easy in retrospect in that Gorbachev had to curb the military establishment's influence and then reside over the Soviet Union's first lost war in order to cauterize the drain in treasure and blood Afghanistan had become. Next came the twin policies of Glasnost and Perestroika: both attempted to address socio-politico-economic problems through two main pushes. Perestroika was to liberalize the economy along controlled market based lines and introduce elections at the lower levels of the state (notable in being as opposed to the party). Glasnost was meant to open up the party to constructive criticism and citizen participation in not just policy, but ideology as well. It was a massive departure from the Soviet Politics of the previous seven decades.

These policies likely had the best only chance for the Soviet Union to modify itself and adapt to a new world paradigm less centered around class and workers rights, and more around globalism and consumerism (a social development Marxism is very poorly suited to tackle). Needless to say, the entrenched elites greeted these reforms with at best mixed reactions, and at worst outright rejection. However, while quite popular amongst the non party citizens and the youth, neither policy could offer much tangibly at first. Elections are nice, but waiting in line for hours to peruse the selection of barely edible vegetables at the state grocery store was much more on the mind of the masses. The market reforms were most likely one of the great examples of "too little, too late".

In the end, neither the Soviet or satellite populace were willing nor were the reigning political elites capable of finding a middle ground or agreement between the lofty ideals of the Socialist Revolution and the grim realities of the totalitarian state required to prop it up. The fact that even in its death throes the Soviet Union and party establishment could undertake such a reform, and that the political leader of the country would risk his position in attempting to implement it is notable. That they were failures was hardly Gorbachev's fault, he was battling uphill in any event, and "business as usual" could have made the collapse worse in the event of a coup of hardliners or a civil war or both with all the horror and bloodshed that could have entailed.