Possibly a few questions.

[c0ncrete]

this should take care of spell casting specialization skills correctly.
i haven't tested it yet, but the syntax is correct and the logic looks sound.

    use List::Util qw(first);

    # shorthand aliases for the client methods we'll be using
    $CanSkill = sub { $client->CanHaveSkill(shift) };
    $MaxSkill = sub { $client->MaxSkill( shift, $class, $ulevel ) };
    $RawSkill = sub { $client->GetRawSkill(shift) };
    $SetSkill = sub { $client->SetSkill( shift, shift ) };

    # set all available skills to max value for client's current level
    # NOTE: spell-casting specialization skills are handled later
    foreach my $skillNum ( 0 .. 42, 48 .. 74 ) {
        next unless $CanSkill->($skillNum);
        $SetSkill->( $skillNum, $MaxSkill->($skillNum) );
    }

    # if client is a caster and can specialize
    if ( $CanSkill->(43) ) {

        # get current raw value for all spell-casting spec skills
        my %spec = map { $_ => $RawSkill->($_) } ( 43 .. 47 );

        # if one spell-casting spec skill is above 50 (main spec for caster),
        # set it to the max value for the client's current level
        # (this skill is deleted from hash and doesn't get calculated again)
        if ( my $mainSpec = first { $spec{$_} > 50 } keys %spec ) {
            $SetSkill->( $mainSpec, $MaxSkill->($mainSpec) );
            delete $spec{$mainSpec};
        }

        # set spell-casting spec skills to max value for client's current level
        # all skill levels but the first one that goes over 50 are capped at 50
        foreach my $skillNum ( keys %spec ) {
            next if $spec{$skillNum} == 50;
            my $maxVal = $MaxSkill->($skillNum);
            $SetSkill->( $skillNum, $maxVal > 50 ? 50 : $maxVal );
        }
    }

NOTE: oops... i forgot to include the List::Util module in my copy/paste. corrected.