Not super sure what you mean. Do you think you can provide screenshots for before/after?

Has a typo in the 2nd remove_meta_box() for non-hierarchical taxonomies, before it should be merged in.

@jtsternberg basically with this one, it allows for adding 'remove_default' => true to the field declaration and have CMB2 hide the default category/tag metaboxes in favor of the CMB2-provided metabox.

$cmb_demo->add_field( array(
    'name'     => __( 'Test Taxonomy Multi Checkbox', 'cmb2' ),
    'desc'     => __( 'field description (optional)', 'cmb2' ),
    'id'       => $prefix . 'multitaxonomy',
    'type'     => 'taxonomy_multicheck',
    'taxonomy' => 'post_tag',
    'remove_default' => true,
) );

TravisCI failed cause PHP5.2 isn't installed or something, understandably so.

Refreshed and merged: 6ee7222
Thanks @c3mdigital!