I understand where Refcat is coming from regarding the proportions of the engine. It looks like the mechanical equivalent of the elephant man or the hunchback of notre dame. I've always looked at these engines as something with a big ole sore thumb.
That being said, in this instance it fits. Let me provide an example where it doesn't. How many people are familiar with the PBS series "A Craftsman's Legacy"? For those that aren't it's about a white-collar worker turn bike builder turn show host running around showing what other craftsmen do. There's one image in the beginning opening scenes/introduction (or whatever you call it) where the host is seen standing in front of one of his custom bikes. It looks to me like a work in progress, but regardless, it's a chopper with either one of these BMW engines or a VW horizontally opposed engine. I'm not sure. What I am sure is that it is one of the butt ugliest motorcycles I've ever seen- production bike or custom- it doesn't matter. It looks like a first attempt at bike building with whatever parts were lying around the garage (I think it might also be shown in the commercials for the show).
This new BMW concept bike, however, does look cool-really cool. It looks retro. It looks like all the descriptors everyone has said about it. I really like that reference to steam punk, and I like the image of the middle finger to HD. Here is an opportunity for an an aristocratic snob to "rub elbows" with the HD crowd without having to lower themselves to wear all the tatoos and stringy beard. The Marlon Brando line is spot on, even though I'm pretty sure he was pure American. I can imagine a Daniel Craig James Bond having one of these in his garage (I know he's a Brit).
Like others, it's not my cup of tea for a primary bike. Yes, it'd be a great bar hopper, but I don't do the bar scene much these days, unless it's at a bike rally, and I ride my touring bike to those. I had a bar hopper that I loved very much, but like a woman who's good in bed and fun to go out with but sucks at being a caring, loving wife, my bar hopper was becoming too problematic. Besides, I can only ride one at a time anyway, and I don't have all that much time to ride to begin with (I'm referring to the bikes).
Like I said. I think it's cool. It's easy on the eyes, and it doesn't look like another freaking HD!
My last point is I'm imagining those German engineers and designers watching old episodes of Jesse James and the other biker build-off shows and singing "Anything you can do, we can do better. We can do anything better than you...." from Annie Get Your Gun.