Shai, can you think of any problems with regard to the null Analnyzer initialization in the DTW IndexWriterConfig?
Now not, I think because of the changes to FieldType in Lucene 4.0. I.e., DirTaxoWriter adds indexed but not tokenized fields. Previously, you had to set an Analyzer, even if you added NOT_ANALYZED_NO_NORMS, or otherwise you'd hit NPE.
If the tests pass, it means it's ok, because DTW is not extendable in a way that it allows you to control how documents are added. But if in the future we'll need to, we'll add this dependency back.