In my opinion, the phrase "based on" implies that a lot of the Elasticsearch functionality is actually Lucene functionality. I disagree that this is the case, I think there is a lot of functionality that Elasticsearch brings that is really othogonal to the Lucene project (sharding, multi-tenancy of indexes, clustering, managing nodes, etc.) Again, you my opinion, definitely enough for it's own project.

If that isn't what you meant then perhaps we are in agreement. :-)