I often hear that a picture says more than a thousand words. Sure do so here. That mainsail dont seem to do much to support the mast.

Nothing wrong with commenting on pictures, especially if it can save a mast or the reputation of a boat/boatbuilder. Is it not? I certainly enjoy comments on my sailing by every Tom and Harry. I even enjoy hearing it from Mr. Dick and consider what he has to say, after all he might have a point which would make me a better sailor.
If we are not here to discuss and exchange experiences, why spend the time on this forum? Pictures are an excellent basis for discussion, even if the team onboard might be olympic class sailors.

On lightweight boats, flat is always faster in my experience. It's in medium conditions and especially with chop fuller sails might shine.