The minimal/empty intersection between coding environments with acceptable performance (Vim, Sublime, etc) and environments with reasonable code intelligence (JetBrains).
Some of above is already there, but they are separate products which don't integrate well. For example: You can find a distributed build environment for .NET & Java. This also runs test, so there is some level of integration. However, I'd also like workflows like refactor-build-test-analyze-fix-refactor until satisfactory.