I believe that it is not so much the shape, but the size that matters.
I prefer a larger bowl for English blends because they burn faster than Virginias. From pipesmagazine radio show, it has been recommended that smaller bowls be used for simpler tobacco (meaning less overall ingredients, like straight virginia), and larger bowls used for blends that have more ingredients in them (like many English style blends containing orientals, latakia, perique, virginia, kentucky, etc). The reasoning behind this was that due to the number of components in many English blends, you would want a larger bowled pipe so that it is more likely to include all the components of the blend. You are more likely to include all the ingredients and taste what the blender intended. If you used a smaller pipe, it is possible that one of the components would not make it in the pinch or two worth of tobacco that fit in it.
I am a slow smoker. A group 3-4 bowl of virginia will last me almost two hours. The same size bowl of an English will usually last an hour.
As far as shapes, I prefer group 4-5 billiards, bulldogs, and apples for my English blends. The majority of my pipes are straight to quarter bent pipes. In my mind, classic English shapes should be used for classic English blends. Honestly though, try different shapes and sizes and find what works best for you. Some people prefer huge freehands and English blends. I find that for my smoking style I have to puff more strongly on large bowls, and that it takes too long to finish the bowl.