This is a required field (http://codex.wordpress.org/Function_Reference/wp_create_user) and I think that more than one function in the core of WordPress relies on that. So I would not recommend to code around it or alter any other WP core files as the next update could render all these changes back to the default values.
Related Posts:
- Filter username field on registration for profanity and unwanted words
- Customize the “Registration complete. Please check your e-mail.” message on WP 4.0
- How To Get User Data in Callback Function for pre_user_nicename?
- How to filter for user registration, be able to throw error message
- Add default user field to WooCommerce checkout [closed]
- Woocomemrce order and registration fileds to UPPERCASE
- Avoid user registrations with specific email provider
- How to modify only part of a function through the filter
- Register new user, assign custom role then send email
- Filter and validate user role in registration
- Custom registration field to SQL database
- Updating User Profile on Registration
- Change password reqts with NO plugin without breaking resetpass link?
- Change or replace user_profile_picture_description filter, to stop stripping whitespace
- Disable emojicons introduced with WP 4.2
- How to remove a filter that is an anonymous object?
- WordPress hooks/filters insert before content or after title
- How to add defer=”defer” tag in plugin javascripts?
- add_action(), add_filter() before or after function
- apply_filters(‘the_content’, $content) vs do_shortcode($content)
- How do filters and hooks really work in PHP
- Trouble understanding apply_filters()
- What is the very earliest action hook you can call?
- How would one modify the filtering Gutenberg applies to pasted content?
- How can I modify the WordPress default widget output?
- Add custom options to the wplink dialog
- Remove classes from body_class
- what is __return_false in filters
- Explanation for apply_filters function and its variables
- Gutenberg: Is there a way to know if current block is inside InnerBlocks?
- How to reorder billing fields in WooCommerce Checkout template? [closed]
- Insert HTML just after tag
- the_content and is_main_query
- Changing WooCommerce Display Price Based on User Role & Category [closed]
- How to add a custom CSS class to core blocks in Gutenberg editor?
- How to show page content in feed?
- wp_headers vs send_headers. When to use each?
- Filter any HTTP request URI?
- How to Pass External Variables to Filters/Actions
- How to filter users on admin users page by custom meta field?
- Filter by one custom field, order by another?
- Not able to change wp_title using add_filter
- How to appending to the_content using add_filter with custom post type?
- Query WP REST API v2 by multiple meta keys
- No filter of code on switch from html to visual editor, how?
- Sanitize and data validation with apply_filters() function
- How to modify posts_where filter only for the search query
- How to hook a filter to catch get_post_meta when alternate a custom field output?
- How to get shortcode’s input values inside a filter?
- Removing Image and Caption Dimension Attributes
- How to wrap oEmbed-embedded video in DIV tags inside the_content?
- How to bulk delete all users with no posts?
- How many filter/action hooks are healthy?
- WordPress 3.9 – Trouble Editing TinyMCE 4.0
- Changing JPEG compression depending on image size
- How to add filter with 2 args?
- Why is javascript allowed in my post content?
- How to use update_{$meta_type}_metadata filter to modify meta value
- How to wrap an element around an iframe or embed in content automatically?
- Filter specific shortcode output?
- WordPress Internal @ Mentions
- How to add headers to outgoing email?
- Earliest hook to reliably get $post/$posts
- Insert new element to array with add_filter
- LESS CSS enqueue_style with add_filter to change rel attribute
- Is it possible to filter comments in a post so a user can only see the comments they have written?
- How to pass/get data to/from the WooCommerce data-product_variations object?
- Remove Editor From Homepage
- How to modify Contact Form 7 Success/Error Response Output [closed]
- Where to hook into post content?
- What does (10, 2) mean when used with add_filter
- Filter translations (gettext strings) on specific admin pages
- Clarification on filters and hooks
- remove_filter( ‘the_content’, ‘wpautop’ ); only for certain post types
- At what priority does add_filter overwrite core functions?
- Unregister Nav Menu from Child-Theme
- Valid characters for actions, hooks and filters
- is it possible to add “extra” table nav to edit-tags.php screens?
- Advanced Custom Fields and Yoast SEO keyword analysis [closed]
- Adding a filter to qTranslate to change display of language chooser
- Insert Custom HTML After Shortcode
- Modify links when inserted by WYSIWYG editor
- Is there a way to add another row to the tinyMCE kitchen sink toggle?
- How to hook into unregistering a widget instance?
- How to check if a hook is hooked or not?
- Completely strip any hidden formatting when pasting into TinyMCE
- How can I extend the Gutenberg table block transform to allow colspans/rowspans on pasted table elements?
- How to add filter to __() and _e()?
- Remove description from on Home
- Editing ‘Password Reset’ E-mail
- Is it possible to use object in add_action?
- add_filter and changing output captions of image gallery
- Passing Additional Parameters to add_filter Callable
- What hook do I use to edit the post statuses option in admin?
- How can I add an Author filter to the Media Library?
- Add whitespace between Chinese and other letters
- Filter hook before create order WooCommerce
- Check if a filter or function has been already been called
- Modify WordPress Rest Api Request/Response
- How to add some custom HTML into wordpress admin bar?