Actually, "use raw parser unless query has dismax syntax" approach doesn't fit, because it kills a lot of useful dismax-related functionality, described here: http://wiki.apache.org/solr/DisMaxQParserPlugin#Parameters.
However, there is a little cleaner solution than what I originally had in mind: "explicitly turn the query into a phrase query (by double-quoting it), unless the query contains dismax syntax". -- Alex Verkhovsky
