Android probably doesn't need a Swift as much as iOSX did, but there's still a lot to be gained from having a less verbose programming language (and corresponding platform API). Objective C, despite its older features and unfamiliar syntax, was more expressive already than Java was. With Swift, they removed the legacy and made the syntax familiar.
But I don't think this is the answer. If you debug Scala on Android at least you don't have to make a mental mapping of what the corresponding Java translation of your function would look like. A true new language with good features and 'light' syntax would be great. Google already has such a language: Dart.
But Google has already said that at IO 2014 that Java is the language for Android and it will stay that way.
Again, this is also not the case with Xtend. See this screencast : https://vimeo.com/38425995
The article felt like it was trying to rationalize something, like Android needs a Swift. I'm not sure that's the case. The main point of the argument by my reading was "less lines of code are possible," but that's not what Swift is trying to bring the to the table (although no header files are nice). Swift's biggest advantage is that since Apple has redefined the rules of the language and don't need to stay C compliant, they can change the optimizer and enforce rules differently. Less lines of code are a side effect.