What did the October manifesto accomplish?
The Manifesto did end up buying the Czar some more time. What was granted in the Manifesto in terms of expansion of political freedoms, representative orders, and voting rights ended up highlighting the fundamental division in the forces which were against the Czar. On one hand, many were in favor of these provisions as they helped to liberalize Russia, bringing out reforms that appeal to a politically liberal base. There were others that felt that these were "token" in nature and not representative of real and substantial changes, noting there was little in way of economic reforms and redistribution of wealth present. In the end, both sides ended quieting a bit, and the Czar understood this as averting or avoiding the issue. His failure was not grasping how to appropriately seize the moment in order to increase his own political viability in a changing setting.
In my opinion, the most you can say for this manifesto is that it bought the Tsar a few more years of power and of life. By October of 1905, Russians were severely dissatisfied with their government. They had lost a war to Japan, there were strike and protests and brutal suppression of some of these demonstrations.
In this atmosphere, the Tsar issued the manifesto, which set up the Duma and seemed to give some amount of rights and power to the people. However, it was a sham. The Tsar could veto the Duma's laws and he could (and did) dissolve it if he wanted to.
So no real change came, and the people continued to be upset.
In Russia a time of the importance of Russian culture and language was developing. The Russians had concerns because the people from Finland wanted to have Russia's protection but did not want to follow the rules of Russian authority and wanted to rule themselves. In February 1899 a Manifesto was established that indicated that Russia had rule over Finland. Needless to say the Finns were not happy.
The Russian government tried to repress the Finns, but the Russian revolution was eminent. The October Manifesto was developed to stop the Revolution by the Tsar reforming the original Manifesto, thereby, appeasing the Finns.