Back in the 70's I had a 125 Kawasaki that topped out at a little over 70mph and I rode at 60mph commuting on 2-lane roads. Later I had a 250 Yamaha twin that would hit 90mph and could cruise all day at 70-75. These bikes made roughly 12hp and 30hp respectively. The idea that you NEED big power to ride on the road is bogus IMO.
Now granted, a big powerful bike is a ball to ride under the right conditions. A nice hilly road with wide gentle sweepers is like being on a roller coaster that's under your control. Also, having power in reserve is a very good thing when the traffic gets heavy and fast.
But to me "adventure" involves dirt and tight, rough trails and that's where heavy and too much power will just give you grief. It's all about the happy medium for me.