UTF8 slug character limit

For utf8 characters (say Arabic, Hebrew etc.) the post slugs (i.e blogname.com/example-of-slug-for-post) are too short. WordPress cuts characters and it is impossible to have a slug with ~6 words. The only workaround in this case is editing the core functions, e.g.:
in wp-includes/formatting.php
$title = utf8_uri_encode($title, 200);
and in wp-includes/post.php
$alt_post_name = substr( $slug, 0, 200 - ( strlen( $suffix ) + 1 ) ) . "-$suffix";
In addition, we have to edit the database structure (wp_posts).
And with every wordpress update it is gone. Can you please make it longer? Or better allow the user to set the max length in config (define some constant).