I'd like the the colour argument for /echo to accept RGB values.

/echo 255 -a this is red!

I don't think the human eye would really be able to tell the difference between 0 to 15 on the RGB scale (I can't anyway), so it could still accept those values as mIRC colours, and people could use 16 for black.

I can't think of a single problem with this method, but I'm sure someone else might.