Provide a way to run Lucene, MongoDB, Neo4j
Azure persistence options don't cover use cases which require a document db or graph db. Azure Drive isn't adequate to port no sql dbs like MongoDB or Neo4J to Azure to handle these use cases, since only 1 role instance can write to the drive.
For the Neo4j graph database on Azure, see: http://neo4j.org/azure
Lucene (or Lucene .net) or some other search mechanism would be hugely valuable. This would be especially valuable if it could be done without needing an entire compute service to do it. It should be built-in to blob/table storage. Maybe there could even be a new storage type: Searchable Storage.