Hi! Very nice plugin!
I’m wondering why the plugin requires to write to wp-content? Isn’t advanced-cache.php the only file it will write in this directory? Setting wp-content writable is almost impossible on many shared hosting. It may be possible to do it for a single file though.
=> That’s why I would recommend to check if file wp-content/advanced-cache.php is writable and if not display the error and prevent the activation.
Also, wp-config.php edit isn’t really necessary as long as define(‘WP_CACHE’, true) is in, right ?
=> I would recommend to first check if this param is in the file, if not and the file is not writable then display the error and prevent the activation.