I tend to make "mini MVC's" with Mason. I find that overabstraction leads to the exact inverse of what you are trying to avoid -- redundant code. And that inverse is a God object that tries to do everything for everybody. So, what i do from time to time is create a top level component that handles CRUD, so my update sub would first call a custom validation sub located in the same package. I set up a messaging system so that if a user enter invalid data, they see the same form with their error messages so they may correct and resubmit. I determine what the "response page" is by calling the proper component. If they entered valid data, that component is the list view. If not, that component is the add_update view again.

This method has worked very well for -- giving me enough abstraction to make laborious tasks more fun while not being too rigid that i have to readdress my design over and over. Here is the update() method of one of these "objects" :

sub update {
    my %args  = @_;

    my @messages = ();
    my @errors   = validate_args( %args );

    if (@errors) {

        # package the errors up as error messages
        @messages = map {{ class => 'error', data => $_ }} @errors;

        # override landing page back to update so user can fix errors
        # $comp is set to 'list' prior to this method call
        $comp = 'update';

    } else {

        my $sth = $dbh->prepare('
            UPDATE thingy SET
                foo = ?,
                bar  = ?
            WHERE id = 1
        ');

        $sth->execute(
            $args{foo},
            $args{bar},
        );

        push( @messages, {
            class => 'message',
            data => 'Thingy successfully updated.'
         } );
    }

    return @messages;
}
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This method is called by a dispatcher which then determines what to fetch:

$m->comp( "comps/thingy/$comp.md", messages => \@messages, %ARGS );
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I hope this adds to the conversation -- I kinda missed what the point was. :/

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(the triplet paradiddle with high-hat)