Regarding maintaining the hulls of the previous boats (37 ans 34 and 42) on the 38, 35 and 41, that hull design is 7 or 8 years old. They modified the transoms, keels and rudders as well as the cabins. It talked with them about it and they said, with some reason, that the previous models are winning races and that some new buyers had the previous models and what they want is the same type of boat but faster with a better interior, that means lighter and with better keel and ruder design since the hull is still up to date.
I guess you are confusing hulls designed to perform better on certain conditions with out dated hulls. I guess you are talking about hulls with all beam brought aft, like on the Dehler. That will improve downwind control and stability (to an extent) but it will be detrimental for upwind performance and pointing ability. It all has to do with the balance on the boat in what regards performance.
See what I mean? Of course these are only 2D shapes but I guess that they are enough to give you a general idea.
I know that the older hulls perform very well and like you i also prefer a more moderate beam. To be honest you have educated me over many posts to understand the advantages and disadvantages of a wider beam taken all the way back versus a more moderate beam. If I were in the market for a new boat, then I would also look for a moderate beam with a moderate freeboard, fine lines of entry with a forefoot that is not too shallow and a hull with some rocker. What I find missing from these older hulls is a chine which assists form stability as you know but which I like the look of. Also I find that in the Salona 35 that the coach roof is too rounded for my liking. A more modern approach would be to have it flatter. Also, i like the option of a bathing platfrom with integrated ladder for chilling at thatbanchorage after you have arrived befiore everyone else
What I am on about is aesthetics more than anything else.
A brilliant boat though and like the Dehler, if it found its way onto my berth, I would be one happy sailor.