I'd like to ask for support for Behaviour Driven Development (BDD) tools

I'll ask for the world first - full integration of Behat (StoryBDD) and PHPSpec (SpecBDD) in a similar way that PHPUnit for TDD is currently integrated would be awesome.

But a nice first step would be support for Behat .feature files, i.e. Gherkin; syntax highlighting, indentation, multi-line arguments - tables and pyStrings

Behat - behat.org
Behat .feature files; Gherkin - docs.behat.org/guides/1.gherkin.html
PHPSpec - phpspec.net

I know PHPUnit can be used for BDD, but I find it a bit clunky - whereas Behat and PHPSpec were built for BDD from the outset

+1, could there appear an integration with Codeception? You may have problems with utf-