I think there are two different types of sailors
The tweakers
and the Non Tweakers
I sailed a Dart 18 for 10 years, followed by a Hurricane for 10 years and then my I17 for the last 4. I bought the Dart 18 becasue at the time it was by far the strongest class in the UK (80's) and was a cheap entry into sailing and because it was a SMOD there was little that changed over time and so running costs were low.
I bought the Hurricane when I left Uni as I wanted a greater challenge and also had plans for a Tornado (and the H59 was the best feeder class in the UK). I was one of the first Hurricane 59 sailors in the country with a kite as I was convinced this was the way to go.
I bought the I17 when my latest crew decided he wanted to do other things and I could not face training up another crew to the level I wanted to compete at.
When I started with the Dart, the simplicity (and thus low cost of ownership) was a big plus and I lived with the fact it was not 100% right/tweekable/ or performed well in all conditions relative to other cats - I was a non tweaker.
The Hurricane 5.9 is/was also a SMOD but still required some tuning / tweaking.
The I17 (in the guise I sail it, ie on handicap) is a more tweaky boat as I have changed things.
As I have got older I have become more of a tweaker/developer of boats.
I enjoyed my time sailing the Dart and Hurricane 5.9 (knowing that all the boats should be the same) but also enjoy sailing my 17 in handicap.
In an ideal world I think most people enjoy both One design class and Handicap racing.
I would love a fleet of 20 I17's at my club (about 200 cats of which only a few actually race) but it is not going to happen so I sail handicap at Grafham (my club)
I also enjoy long distance racing on the 17, which by definition is always handicap.