Customers used to complain that the tooling for creating BI projects (Analysis Services MD and Tabular, Reporting Services, and Integration services) has been based on earlier versions of Visual Studio than the ones they were using for their other work in Visual Studio (such as C#, VB, and ASP.NET projects).
To alleviate that problem, the shipment of those tools has been decoupled from the shipment of the SQL Server product. In SQL Server 2014, the BI tooling isn't even included in the released version of SQL Server. This allows the team to keep up-to-date with the releases of Visual Studio. A little while back, I was really pleased to see that the Visual Studio 2013 update for SSDT-BI (SQL Server Data Tools for Business Intelligence) had been released. Unfortunately, they then had to be withdrawn.
The good news is that they're back and you can get the latest version from here: