If you don’t need to use SKUs at all in your shop, you can disable them completely by using this plugin.
This plugin should work with any WooCommerce installation, since it hooks up to the core functionality of WooCommerce. Note that at least version 2.1.0 of WooCommerce is required.
== Installation ==
- Download the archive and unzip it in /wp-content/plugins, upload the archive at Plugins > Add New > Upload Plugin or install via Plugins > Add New > Search for the plugin name in the search bar.
- Activate the plugin through the Plugins menu in WordPress
- Update the plugin settings in your WooCommerce settings at WooCommerce > Settings > SKU settings pages.