Attempt 2. Details: http://sridharkatakam.com/display-full-content-category-pages-selected-categories-genesis/

functions.php

<?php

add_action( 'genesis_before_loop', 'sk_full_content_specific_category' );

function sk_full_content_specific_category() {
  if (is_category('featured')) {
		// remove_action( 'genesis_post_content', 'genesis_do_post_content' ); /* Pre-HTML5 */
		remove_action( 'genesis_entry_content', 'genesis_do_post_content' ); /* HTML5 */

		// add_action( 'genesis_post_content', 'sk_do_post_content' ); /* Pre-HTML5 */
		add_action( 'genesis_entry_content', 'sk_do_post_content' ); /* HTML5 */
	}
}

function sk_do_post_content() {

	global $post;

	if ( is_singular() ) {
		the_content();

		if ( is_single() && 'open' === get_option( 'default_ping_status' ) && post_type_supports( $post->post_type, 'trackbacks' ) ) {
			echo '<!--';
			trackback_rdf();
			echo '-->' . "\n";
		}

		if ( is_page() && apply_filters( 'genesis_edit_post_link', true ) )
			edit_post_link( __( '(Edit)', 'genesis' ), '', '' );
	}
	elseif ( 'excerpts' === genesis_get_option( 'content_archive' ) && !is_category('featured') ) {
		the_excerpt();
	}
	else {
		if ( genesis_get_option( 'content_archive_limit' ) )
			the_content_limit( (int) genesis_get_option( 'content_archive_limit' ), __( '[Read more...]', 'genesis' ) );
		else
			the_content( __( '[Read more...]', 'genesis' ) );
	}

}