Libraries as "One-stop-shops" ?

A few years ago there was the common opinion that libraries have to be "one-stop-shops". Recently there is a tide against it: Ojala is one of the detractors who is saying that the disciplines are too specialized to be covered by one global search (e.g. vascoda for specific/ technical information). Furthermore you only can develop a meta-search with search functions that are included in each of the databaeses, catalogs and/ or search engines.
In Germany there is one meta-search example in the field of LIS: b2i.

These are a few of the problems that one is facing while developing an optimized service to customers. But nevertheless the library portal has to become a "service oriented architecture": Everyone knows the information architecture that is connected with or part of a library portal:
No wonder that a customer gets confused! Even a librarian does not know all these online services.
That's why the library portal has to be changed into an intuitive and easy-to-use portal. In my opinion this is a major task of librarians.