i wouldn't say it's complicated, just wasteful since it relies upon a response from the server containing data that is already computable given the information stored by the client (the pertinent data at least).

you should be using 'iswm' instead of 'isin' for it to be functionally similar to the original code. also, you may use $fline() to find nicknames that match a certain wildcarded pattern in a given channel. for example:

var %t = 1
while ($fline($chan, $1, %t, 1).text) {
  echo -ag -> $v1
  inc %t
}