I missed the "debates", both of them, but I've heard that Duceppe kept bringing up the European Union as an example of the sort of thing that most sovereigntists want. I haven't explicitly independently verified this claim (can someone in the comments?), but I can well believe it, since it's something that Quebec nationalists have been mentioning as a model for a long time. In frustration, even Robert Bourassa brought it up as a potential future model for Canada.
I can perhaps comprehend the frustration, but I can't really understand the example. Particularly bringing it up now, if Duceppe really did so. In the case of Bourassa, he likely fundamentally misapprehended the direction of the EU process, which at the time would be rather easy to do. In the case of sovereigntists now, it could only be an outdated concept of what it really is.
It strikes me that the EU is an example of many things that are precisely the opposite of where Quebec nationalists (of both federalist and sovereigntist stripes) want things to go. Most francophone Quebeckers could be persuaded to accept a deal that leaves defence policy and foreign policy in the hands of Ottawa. It is most other areas of policy in which Quebec nationalists want Ottawa to avoid interference. Ottawa, in this view, has no role in encouraging policy uniformity in the country as a whole.
But the EU leaves each member with its own sovereign personality as expressed via foreign and defence policy. Instead, the EU acquis communautaire specifies all kinds of limitations on members on every aspect of domestic policy in order to obtain EU-wide uniformity in various dimensions. Quebec sovereigntists would be howling with anguish if Ottawa had anywhere near the interfering ability that Brussels has at least technically on everything but foreign policy and defence, where the EU has been rather slow to merge.
And that's just the EU as it is now. Worse, the tendency in the EU, despite the setback of the EU constitution, is still, last I checked, rather centralizing. They already have a single Parliament with party politics---a Parliament that is chomping at the bit to take over more and more of what appear to be domestic issues. There are equalization payments. There are budgets and ministries. Over the past view years, very much the opposite tendency of what sovereigntists want.
And that's something of which apparently the sovereigntist movement, at least its mainstream, hasn't really seemed to grasp the causes. The world does not, for better or for worse, see the ability to set social policy or health policy or whatever to be the sign of a sovereign people. Formally abandoning these powers to a higher entity is par for the course in this world. What the world recognizes as true sovereignty is what the EU states still retain: the strongest powers of violence. And that's not an accident either. It's related to issues I discussed in my post on the unavoidability of all-or-nothing solutions to Quebec-ROC relations.