I was reading the MSDN magazine March 2013 and i found an article by Julie Lerman about EF 6 Alpha features.
If you haven't had the chance to read the article, here is a summary of this article for .NET developers and architects:
1) EF 6 will be supporting multiple schemas. So in your dbml file you will be able to reference and import multiple schemas in your database.
Julie has written a detailed article about this feature, here is the link for this:
2) EF6 will be supporting the asynchronous processing (Async).
Since we have Asynchronous pattern supported in .NET 4.5. The EF 6 will be bringing some of these features by having: SaveChangesAsync(), ExecuteSqlCommandAsync and FindAsync() functions that don't block the UI while executing and you will be able to write asynchronous code in your application in EF 6.
For Linq to Entities, they have added bunch of other Async methods for enumerations such as: ToListAsync(), FirstOrDefaultAsync(), MaxAsync().
This is a very important feature especially for Silverlight, WPF and Windows Phone developers in addition to web developers.
3) Enum and Spatial support
EF 6 will be supporting enums and Spatial data types. Unlike earlier version where dependent on the .NET framework you are using/targeting. The new EF 6 will be supporting this no matter which .NET framework you are targeting. So you can use enums and spatial support even you are targeting .NET 4.0 framework that doesn’t support certain EF 6 features.
Hope this helps.