I think that the "rulemakers" are thinking about the faster boats, that is why they changed the two-length zone to three-length zone.
http://rrsstudy.blogspot.com/2008/06/new-rule-18-three-length-zone-in-rrs.html
(Checkout the rest of that blog as well, very interesting reading).

IMHO sailing is a complex sport and I think that if you would start out with maybe 5 rules,
you will find yourself adding a few rules every race because there is no way those 5 rules would cover every possible situation.

Speaking of slow boats, did u guys read the header of one of the SA news topics? It has to be the best ever:
"4 Knot Sh!t Boxes Dominate" (Its about the Newport-Ensenada race).