Information overload is apparently not a new phenomena but was already noticed by Morris L Cohen, co-author of How to Find the Law (pdf), in 1968:
[…] the materials of our law seem to be marked by an accelerating birth rate, an almost non-existent mortality rate, and a serious resistance to contraception on the part of both judges and legislators.
Morris L Cohen; Research habits of lawyers; Jurimetrics; 9:1968; pp 187–188
Maybe the delete movement within privacy could offer a solution here, allowing for non-relevant legislation and case-law to be deleted as it becomes obsolete. For example, non-referring to a specific statute or case for several years could lead to its deletion or it being moved into the to-be-inspected archive folder maintained by a newly appointed Authority for Quality Assurance within Law – AQAL.
Spring cleaning in the repository of legal information retrieval – the legal sources – would not only lead to more coherence within the law but, above all, improve retrieval of legal sources and the quality of legal research.
[NB] See also the earlier quotes of the month:
iinek's blog 
Information overload is a growing issue in society generally, and law reflects society. A very though provoking post.