My preferred touring setup:

+

Regardless of what people think, the majority of power in a pedal stroke is directly DOWN. The pulling effort adds virtually nothing to your stroke, just as long as you unweight your pedals, your good. What clipless does well (relative term) is in keeping your feet positioned optimally as your ride. Side effect is knee issues if things don't line up properly, obviously not an issue for flats/clips/etc.

Ive said it once and I'll say it again, clipless is much better suited to racing, which is what it was designed and developed for. Some will disagree, but I don't see any point in using them on a touring bike. People that downplay them have either A) not used flats, B) not tried them with an open mind or C) are not being true to their needs.