The argument that winning big states is more meaningful than winning small states smacks of whininess -- the nomination rules are the rules. This argument is often conflated with, for Democrats out of coincidences of geography, "wins in Democratic states are worth more than wins in Republican states". However, I wonder if the arguments are doubly flawed.
One rationale for the argument appears to be: Obama's wins in traditionally Republican states are less meaningful than Clinton's in states where Democrats can reliably win. The argument would thus seem to be: if Obama becomes the candidate, our grip on those Democratic states will be put at risk. But isn't this backwards? Isn't it the case that Obama has stronger support in states that Democrats need to win (i.e., Republican or swing states) and thus wins in those states are more valuable? Especially to the extent that his wins come from drawing independent voters that Clinton was apparently less able to draw?
The other rationale is that primary wins in big states translate into wins in the general election. For this to be true, it would require either (A) that Democrats (in this case) turn against or choose not to vote for their party candidate in the general election and/or (B) that swing or Republican voters are more likely to choose the primary winning candidate than the alternative Republican. Because A seems unlikely, I think B is left as the rationale. A shaky rationale as B's accuracy depends upon the identity of the candidate fielded by the other party. Meaning that the right test is how the Democratic candidate matches up against a specific Republican in the various contested states.
Simply said, because (i) the primary process tends to produce candidates who have successfully presented themselves as a party standard bearer (meaning less centrist) and (ii) winning the nomination doesn't give a lot of insight into how a candidate will appeal to the general population, drawing any inferences or making predictions based upon success in a type of state is stupid.