I think looking at the specifics of the 1905 Revolution are extremely helpful in relation to this debate. It illustrates the confluence of agrarian reform and industrialisation as being the main destabalising factors within Russia at the end of the 19th century. It also has the direct parallel with the unsuccessful Russo-Japanese war (vrs WWI) replete with military mutinies (Sevastopol,Kronstadt, Battleship Potemkin etc.
Therefore all the factors that came into play in 1917 were represented then, 1905 was a dress rehearsal for 1917 if you like and explains to me why the end, when it came, was so swift.
A large part of Alexander II's motivation in liberating the Serfs was to enable a free movement of labour essential to successful industrialisation. It was at this point that the creation of a real urban working class in Russia really came about. At the same time in the countryside the newly freed peasants were initially given some form of political representation at a local level in the form of the Zemstvos.
These were supposed to help sort out the multitude of new problems the emancipation had unleashed for both ex serf and landowner alike, redemtion Tax, sale of land etc.
Alexander III on his accession to the throne effectively removed the Zemstvos, and replaced them with the 'land captains'. This exacerbated all the problems for both ex serf and ex owners and led to an almost complete breakdown in local administration throughout the Empire. It also created enormous disaffection not just in the peasants and urban workers but the landowners aswell, all of whom were effectively made worse off by Alexander III's attempts to reverse the effects of the emancipation but not the act itself. A perfect example of just how much the mechanisms of state had been weakended is the chaos that ensued with the Cholera epidemic of 1891.
Therefore by 1905 there were several large but very diverse agitational components within Russian Society. Both the peasants and the new urban workers had been given citizenship but no actual freedoms whilst at the same time policies promoting industrial growth were being aggressively persued. This contradiction deprived Russia of the successful industrialization she sought and meant that Russia's landowning class were also materially worse off. It also meant that Russia was unable to compete militarily, the infra structure was simply not there. This in turn led to disaffection within the military aswell.
The post 1917 communist rulers of Russia have peddled the myth that it was one people with one agenda rising up to overthrow a tyrannical regime. It was not of course. It was many many diverse factions sometimes fighting for common goals sometimes not. It was the radicalised urban workers typified by Trotsky that took charge of Petrograd at the crucial moment because they happended to be in the right place at the right time. The Civil war further shows that the Bolsheviks did NOT speak for the majority of Russians. Between 1921 -1926 there could have been a move to some sort of genuine political reform but the appearance of Stalin ensured that did not happen.
Therefore in relation to Alexandra, all the diverse elements that led to the dynasty's downfall were very in much in place and on the move by 1905, Nicholas tried a liberal approach and then a hardline one in response, neither worked and not just because he was ideologically opposed to the liberal viewpoint. I apportion a large part of the blame directly to his father for this NOT because he was a reactionary but because he crippled effective local administration throughout the empire, which for me was the single deciding factor in why their was so much unrest by 1905 and a complete lack of the necessary infrastructure for Russia to compete militarily both in the Russo-Japanese and WWI.
Those are the reasons the dynasty collapsed. All that the arguments for Alexandra's influence have shown (in my personal opinion) is that she was unpopular because she happended to be a German at a time Russia happended to be fighting a war with Germany and was always personally unpopular with the Tsar's relatives. That however cannot be considered even a factor in the regimes collapse because it was entirely symptomatic, not in any way a causation of the failure to industrialise based on a fundamentally ideological conflict because Nicholas tried both broadly liberal and the hardline approaches, neither worked, because the damage had already been done in the previous reign and WWI just brought it all to a head.