Wouter
If we go back to what I understand Jim's original design brief was - carry weight + line honours I would say that it looks to be in the ball park and that the designer looks to be well on his way to fullfilling the brief. I don't believe it was intended to be a big leap forward in design so it would be diffficult to criticise him for not having done so.
Re the weight I am not talking about 160kg's helm and crew but something a tad higher and I do not believe that many F18's carrying >190kgs are competitive - IMO.
The RS600 may not be an international boat but how many RS boats are? It doesn't make them or the designers less effective. The dinghy market in the UK dwarfs the Cat market and my strolls through French sailing clubs tell me that the opposite is true elsewhere. To have introduced a sucessful boat into the UK against the well established Contender took some doing. And as regards "just that his history doesn't necessarily garantee a succesful cat design to come off his drawing board" - nor I suspect would anyone elses for that matter either!