Whether any of the secondary focus points on your average dSLR really improves on focus and recompose at f5.6 probably depends on your lottery number.
Edmund
If your cameras secondary focus points are accurate you are more likely to get more accurate focusing that focus and recompose for several reasons.
First of all with fast focusing lenses you focus right up to the instant in which you shoot the image.
With focus and recompose you have a delay while you recompose so if the subject moves forward the focus locked before
re-composition will be off. Also in my experience a model that is going through different poses always creeps forward.
When focus and recompose is used when the photographer his head has to tilt down. The fulcrum on which it tilts down is
below the cranium and a few inches behind the camera. Due to this the camera is going to move forward and the head tilts down.
This moves the focus plane even further back. Using a tripod will be similar as the rotation point is well below the camera.
There is also another reason why this whole focus and recompose issue is a problem and it is the high resolution of
the files. Art directors expect to be able to crop images quite a bit and we all know the closer you crop in on an image the more you see and focus errors.
It also depends somewhat on what you photograph.
If you shoot models they don't have much to do with the final selection of what is published.
No problem for the photographer to ditch the slightly off focus ones.
If you shoot celebrities for example it is not uncommon for the publicist to insist on reviewing
the images and choosing the one's to run or at least participate in the choice.
It's really annoying to have to tell them that an expression or pose they like should be rejected because of a focus error.
Then there is the issue of wiggling the camera infront of your subject. Focus/recompose again and again... wiggle wiggle wiggle.
Personally I don't find it conducive to creating a mood or atmosphere.