Q: wordpress multisite remove /sites/{ID}/ automatic upload url when using wp multisites it gets messed up pretty fast.
Is there any solution available removing the automatic /sites/{id}/ folder structure?
I'm able to adjust the site-upload-dir within site-settings but it always adds " /sites/{id}/ " to the uploaded file through the media-manager.
Is there any snippet available removing/disabling these extra folder structure?

A: First I ended up changing the core in wp-includes/functions.php in order to disable the addition:
if ( defined( 'MULTISITE' ) )
    $ms_dir = '/sites/' . get_current_blog_id();
else
    $ms_dir = '/' . get_current_blog_id();

And one line below that my hack:
$ms_dir = '';

But after a while I found this solution where one can use a hook. Example:
add_filter( 'upload_dir', 'same_upload_dir' );
function same_upload_dir( array $uploads ) {
    $baseurl = WP_CONTENT_URL . '/uploads';
    $basedir = ABSPATH . 'wp-content/uploads';
    $subdir = $uploads['subdir'];

    return array(
        'path'    => $basedir . $subdir,
        'url'     => $baseurl . $subdir,
        'subdir'  => $subdir,
        'basedir' => $basedir,
        'baseurl' => $baseurl,
        'error'   => false,
    );
}

