[Barnsnake]

I have a bit of a problem with the author's example. The model airplane engine is probably a cross flow two-stroke and the marine engine is a four-stroke deisel.
The airplane engine might be good for 100 hours, while the marine deisel is designed to run 50 years. Comparing apples to oranges (or is that peas to watermelons?).

Torque is force times lever arm. A longer stroke results in more leverage and therefore more torque at equal bore and cylinder pressure. I don't want to rekindle the torque-vs-horsepower argument, but horsepower is a function of torque.

Whether you want a long stroke or short stroke motor is a matter of application.
Personally, I think a big, broad stroker powerband is nice in a road car. For the drag racer that only runs below 6000 rpm in the staging lanes, the broad powerband is useless.