Well, I only agree on the 'for' loop suggestion and your suggestion regarding strings to be placed in quotes. The for loop is a suggestion that has been regarded many times, who knows why it hasn't been added, but the quotes would be a pleasable feature. This could eliminate all of the problems with using the comma in identifier strings, such as:
$input(Welcome! In order to begin[b],[/b] please click the 'ok' button below.,io,Welcome)
Would be nice to see this, but quite frankly, mIRC would have to remain backward-compatible with the alternative method, providing the capabilities of old scripts to still 'have a chance' at running. Who knows, maybe this is possible?