That Benelli looks a little like a Kawahama Omnistrasse.
The assumption that a taller front wheel rolls easier over obstacles is a given, and personally, I think my 19" is a pretty good trade-off between a great handling, wide, 17", and a tall, easy-rolling 21". I haven't yet dragged my pegs, but my Tiger is every bit as fast through the twisties as any of my friends' bikes. (Keep in mind, that I try never to ride with more experienced riders. Fragile ego, y'know. :

)
There's also those old black-and-white movies showing Model A's bouncing through axle-deep mud with those skinny tires. Maybe they only show the one's that got through, but they sure look unstoppable. Not sure they'd make it as far on 275/45-16's.