Provide (better) support for distributed transactions
Of course it is already possible to handle distributed transaction e.g. by using MSDTC. But compared to what's possible in the Java world, this method feels a little 'outdated'.
Additionally, because EF7 will get Support for non-relational data providers there will be a strong need to handle distributed transactions that involve relational databases and non-relational datastores within the same transaction. Think of scenarios where a document, image, movie clip is stored in NoSQL datastore but its index fields, metadata and so on may have to be stored in a SQL database.