I am not - by any stretch - an expert on national unity matters, at least no more than any other Canadian is these days. But a few thoughts on the Liberal motion:
1) If it means anything, it's a bad idea to support it - if we're recognizing "nationhood" for Quebec, and that ends up meaning devolution of powers, or a veto over ammendments to the Constitution, this is a much, much larger and longer process than a majority of the Quebec Liberal Party has the right to inflict on the other 30 million of us.
2) If it means nothing, it's a bad idea to support it - if we're recognizing "nationhood", and then refusing to allow any conclusions to be drawn from that recognition, this is a waste of time. As a rule, you don't write something like "Quebec is a nation. So what?" in to the Constitution. This hasn't stopped Michael Ignatieff from arguing essentially this position.
3) Supporters of position #2 are forgetting - or never learned - that you don't win a political argument by conceding the other side's rhetorical points. If you are a federalist, it is difficult - though I concede, not impossible - to convince the people of Quebec that they a) are a "nation" (however you define the term) in fact and by right, b) have excercised a huge spectrum of autonomous powers for more than a century now, BUT c) the separation of Quebec from Canada is a bad idea, or simply wrong.
I would note, regarding point #3, that Stephane Dion has made exactly this argument against both "nation"-hood for Quebec and the "fiscal imbalance". Both are issues dear to the hearts of separatists, and when the Liberals go conceding both arguments to the other side, they make it more difficult to win the overall argument.
Finally, and I don't think this can be said enough: Separatists are, regardless of their actual numbers in Quebec, extremists. (Here I am not referring to what others have called "soft sovereigntists" who support the BQ or PQ but not necessarily full separation.) They are seeking the most extreme possible solution to their grievances, and are not interested in "concessions" from Ottawa, except in the sense of getting Federalists to provide the rope to hang themselves. We cannot bargain our way towards their happiness or satisfaction. The one thing a resolution like this can never do is solve our unity problems in Canada. Like I said, I'm not an expert on these matters - I don't know the secret to ending the unhappiness of some Quebecois within Canada. But I cannot imagine that this is it.
All that said, I would love to see poll numbers (if anyone has them) of how Ignatieff's proposal (meaningless recognition) actually plays in Quebec. I'm entirely willing to revise my theses if evidence proves me wrong.
Paper Dynamite Online has been doing yeoman's work on this issue - for more intelligent analysis, go read him. See especially this - it seems that the resolution changed from something that Dion couldn't support, to something that Dion already supported, after the vote. Shenanigans, I say!