ZippyV said:
Charles said:

We need native code to get other browsers on WP7. The built-in browser is not up to par with the current standards and is therefore useless.

Strictly speaking, native code is not necessary for such a thing, but it would mean that you would have to write your browser from scratch and it will be difficult to predict how it will perform. Either that, or someone will need to figure out a way to compile native code into MSIL.