People are overreacting a bit to this. Just because the borg are jazzing up their music a bit and being a bit more expressive about it, it hardly means they are becoming Pentecostal. The GB have probably been advised that statistically, young people and families are turning to the more modern, contemporary style churches because they provide a satisfying emotional experience. The org has never really provided that, relying on a traditional catechism style service or treating meetings like a franchise meeting of a global religious sales company (which is ultimately all the religion is).
It's all part of a strategy to give the turd a more modern, 21st century polish to try and stop the haemorrhaging, nothing more. And to make it more palatable to the African and Latino contingents, where the only growth is now occurring.
What I find disturbing is how they are increasingly using video technologically at their large gatherings in an Orwellian way, portraying horrible doomsday and obedience themes on a big screen. Its screaming out for an expose on 60 minutes or something.