Actually pheonix $2- was correct if they are going to type it in input event. Ex: The user types
/msg #mychan hi
that would trigger the id == /msg and the $2 = #mychan $3 = hi
where as your saying /msg # $2- which is now:
/msg #typed-in-chan #mychan hi
as for redifining captain_obvios, try this:
alias msg {
.msg $1-
/echo $color(own) -ti2 $1 (theme here)
}