A week or so ago, there was this article in the Chronicle of Higher Education that suggested that the problem is not one of LPUs, but instead of useless and boring research being published, wasting everyone's time and resources. Female Science Prof has an awesome refutation of this article, with Drugmonkey adding some additional arguments against. For the other side, Derek Lowe agrees with the CHE.
This topic touches in some ways on my previous post on old, abandoned data. Personally, I think the problem of old abandoned data is more significant than excessive publication of results. I've seen this play out in my own career. When I switched to a new research focus area, I aggressively searched out techniques that would speed our progress, only to find nothing much published that was directly relevant. Some of the stuff I did find was from the 60's and 70's, with low citation counts. This stuff was incredibly useful to us, even though it had lain fallow for 30+ years before someone found it worthwhile.
I've also seen the opposite occur. We had some incidental findings that we didn't think worthy of a separate publication. A few years later, another group replicated and published our (unpublished) "incidental" results. Their paper has been cited 12 times in the year and a half since publication in a field-specific journal with an impact factor of 6. It is incredibly difficult to predict in advance what other scientists will find useful. Since data is so expensive in time and money to generate, I would much, much rather there be too many publications than too few (especially given modern search engines and electronic databases).