John,
I agree with everything you said and wouldn't mind racing in the same atmosphere. However, you're moving farther away from 'one-design' and have made some sort of compromise that lies between true one-design and box rule. If it works for the Tiger class, that's fine, but just because the hull and board shape is the same, by definition, this does not make it a one-design class. By the time we've made all these compromises, why not simply adopt the F18 rule and apply it to the one-manufacturer class?
I think the ultimate solution (it was said above) is for each manufacturer of an F18 to commit to the fact that they are producing an F18 and let F18 rules apply. If the boat owners support it, have your own nationals or worlds but keep things simple by allowing all your customers (in this case, Tiger owners) to compete by aligning the measurement and rules with F18. This is such a simpler way to go.
I for one, would like to see all manufacturer nationals to be opened up to any F18 - They're building it for that purpose right? Why all the confusion? Showcase your product! Just look at the example Europe has provided - F18 is rockin!
The only argument that I've heard against going true box-rule F18 for individual manufacturer classes is that the sailors don't want an 'arms race'....has anyone seen that yet? Ever argument pro or con above indicates there's no significant competitive disadvantage to all the changes - so why resist the already existing rules?