Looks like you guys want to have the cake and eat it too
Will you guys also be using JSON style name/value pairs to create heirarchical data structures with the "dynamic" data type? I am guessing you will allow the developers to also "augment" the "dynamic" data type in a similar fashion. If you do, how are you going to provide for encapsulation (everything is public access)
The covariance and contravariance stuff is cool. When I saw the example, I was thinking "duh, but of course"
I like the optional/default parameters and named parameters too. I have been wanting that for atleast 4 years now