I think there is something about about highlight roll of gh2 which made it the most cinematic looking camera and i haven't seen that in other dslr or mirrorless cameras ( looking at the footage on the net). like you I'm also planning to go for gh4 and like you i'm looking for some footage that will make me go for the camera. here is something i think is good looking footage of gh4 but still not impressed as gh2: https://vimeo.com/107965238
4k was already there long time back when Red cameras were introduced. So I don't think it is the matter of resolution but the accessibility. Not every aspiring filmmakers can afford or even rent such cameras. possessing a cinema camera is i suppose every filmmakers dream. I know, resolution is just one aspect, but still to satisfy your soul- to own a camera which we assume are little brothers and sisters of the High end cinema camera definitely helps.