I think you hit the nail on the head. Casey IS a great model for vloggers because he's introduced a sophistication to the medium that was previously lacking. I love his run-and-gun style of storytelling, which is perfect for his 10+ minute YouTube movies, but to try and sustain that over 90-120 minutes? I don't think so.
That said, I do wonder about the impact of smartphones, YouTube and social media on feature filmmaking. As our attention spans continue to grow smaller and we continue to watch more content on phones and tablets (not the mention the lowering of obstacles and gate keepers to getting filmed content produced and distributed), how will this impact the film industry and our collective appetite for movies? This, to me, is a watershed moment, and to hear people hailing people like Casey Neistat as the harbingers of a new style of movie making makes sense. I just hope they're wrong.