That's not that different to what I am saying. Except I think most people are riding in adequate volumes. A couple of extra inches in length, a little bit more width, a bit more meat in the foil...lots of ways to get more volume. I am certainly not saying go to 3 1/2.
But conversely, you can also lose a lot of thickness before the rail and still have it sensitive.
My last two boards, both guns, have been 3" or thicker and yet quite pinched rails. I have ordered two more from a different shaper who looked at the curves in Te bottom, the rocker and the rails and said he wouldn't do it that way. Which is why I went to him. He also said it wasn't that my boards wouldn't go, just not go how he wants. The new boards will have way different bottom contours, markedly thicker rails, and significantly more rocker. I expect they will go well. When I get them I will have had 9 boards off one and 7 off the other and only one dog out of the 16. There's nothing wrong with different philosophies toward rails, rockers, outline, bottom contours. If there was a perfect board we would all be on it.
But, whether it be through nose width, centre width, length or thickness, I think most people are riding boards without enough volume.
Keep the same model, just add three or four inches. And don't think just because your 5'8" board can surf 2-8' that it is the best shooter for the top end of the range.
Having said all that, people being undergunned certainly makes getting waves down here on solid days easier.