Canada is a very large nation and it makes sense that people would naturally want to separate a little from people they view as other culturally. However, this separatism does prevent the country from being unified. There is no way you can have a truly unified country if you agree with separatism.
Quebec seperatism within portions of the Quebec population does prevent Canada from truly being a unified nation. There is a large disagreement between the groups of people that this situation affects and it causes a problem for the local and national governments. The situation can not easily be resolved in the short term.
I do believe that while there is a sizable number of people who wish to see Quebec split off and form its own nation I believe that the vast majority wish to remain part of Canada, I think overall most people in Quebec and overall in Canada consider the entire Country to be unified as one.
No, the obstacle of Quebec separatism within portions of the Quebec population does not prevent Canada from being truly unified as a nation, because vast majority of people in Quebec do not want to be independent. There are people in Texas and California that want to be independent too. That doesn't mean we're not unified.
I do not believe the obstacle of Quebec separatism within portions of the Quebec population prevent Canada from being truly unified as a nation. I believe the supporters of this movement have elected to only take a democratic approach to separating and while the do seek supporters I don't think it's at the expense of Canadian unity.