Problem with "implementing" such features is that when do you (or Khaled for that matter) decide what to implement and what not to? Obviously, it is impossible for Khaled to support every feature there is. And some networks have features that are totally different from what's specified in RFC 1459. Others may conflict with another networks feature (same mode used to signify different things, etc.)
As it stands, mIRC implements a lot of features that are network-specific. I'm sure if there is a proper demand for it, Khaled will consider it in the next version. If not, then you can always script around it for the time being.