Check out http://tinkerpop.com. Apache TinkerPop 3.0.0 was released in June 2015 and it is a quantum leap forward. Not only is it now apart of the Apache Software Foundation, but the Gremlin3 query language has advanced significantly since Gremlin2. The language is much cleaner, provides declarative graph pattern matching constructs, and it supports both OLTP graph databases (e.g. Titan, Neo4j, OrientDB) and OLAP graph processors (e.g. Spark, Giraph). With most every graph vendor providing TinkerPop-connectivity, this should make it easier for developers as they don't have to learn a new query language for each graph system and developers are less prone to experience vendor lock-in as their code (like JDBC/SQL) can just move to another underlying graph system.
Its more about data interchange support, i.e. we could support GraphML instead/next to the RDF varieties.
But this would be difficult for us to generate in a streaming way.
Then for our end users, we would need to hack in a namespace convention to avoid issues when integrating our data.
Then TinkerPop misses the SERVICE concept for federated querying in SPARQL1.1, which is essential for our endusers who do knowledge discovery (i.e. small biology labs without the inhouse capability of running their own large databases).