I tend to slightly disagree on your second point. While we may not have seen new designs as 'disruptive' as the Capricorn at the time (quickly followed by the Infusion) during the past few years, I would say that the latest designs still tend to outperform - albeit arguable in a narrower range of conditions.
At the same time my impression is that the current performance gaps between models are now so narrow that not many of us F18 sailors think that they can only have fun and do well in regattas if they buy the latest that's out there.
My experience is that F18's have become even more fun to sail then before.
This is the result of continuous development, which over time has led to a steady improvement in not only speed, but also on other important points like handling and 'safety': newer designs - including the Infusion - are less vulnerable to cartwheeling as result of increased hull volume and better bottom shapes.
Also, my impression is that product quality has improved over time (albeit sometimes with hick-ups).
The combination of class rules and the force of competition have led to great progress in the class thus far, with its sailors reaping the benefits.
I look forward to seeing you again during our spring regatta!