[selectors-api] Return an Array instead of a static NodeList

Since Javascript 1.6, a lot of useful collection functions are defined for 
Array [1]. Unfortunately, they can’t be used directly with results returned by 
.querySelectorAll, or even .getElementsByTagName since these functions return 
NodeLists.
I understand the DOM API is defined without a language in mind, but these 
collection functions are really useful, easy to implement and already 
available in most mainstream languages. Therefore, why not create a base 
Traversable type which would be implemented by all collection types (like 
NodeList) and which would provide the so useful bunch of iteration methods? 
Are there some issues or drawbacks I did not think of?

Regards,
Julien

[1] 
https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array#Iteration_methods