This trend of newspaper consolidation of operations is not going to be perfect.
I work for a chain of about 20 papers, as editor and publisher of a small weekly and a very small weekly. We have a single ad-building department for all papers at the "home office" that isn't the "corporate headquarters," according to powers that be.
Given the volume of stuff they do, the error level probably isn't horrible. But, it's an issue of communication, when you're dealing with that many newspapers. Just like with consolidated pagination sites for that many papers, you're going to have an increased error level. Plus, because things aren't "local" any more, it's easier for stuff to kind of fall through the cracks.
And because a lot of these consolidation efforts are based on small, community-type dailies, and even more community non-dailies, don't think that the decline in ad revenue, circulation or both will be an issue just for big papers.
I don't have an answer for it, and I do know that it saves money. At least in the short term. But, if quality concerns in the longer term get serious enough, it may not be a long-term money saver.
At least the ad side isn't as bad as the pagination side, if you're doing multiple daily papers on deadline, and breaking AP news demands a change in front page and jumps at multiple newspapers at the same time.