One general question:
My last patch also removes the ISOLatin1AccentFilter, because it is deprecated. The problem with removing this filter is, that current indexes cannot be used anymore, because you have no possibility to add new documents using this filter in 3.0 or do queries with accents against it. Maybe we should leave this class deprecated alive or move it to contrib? Or we force people to reindex.
The same applies to DateField from the o.a.l.document package. It is deprecated, so no one should use it, but we cannot remove it, because existing indexes need this support. This is different for e.g. Field.Store.COMPRESS, because you can still read the indexes (decompression is automatically), and can add new content without compression. Or reindex and use a own compression using byte stored field (as suggested).