I could see him getting a lot of the Goyo stuff as level rewards, most of which isn't terrible. (Chaser and Predator would be quite nice.) Probably at least 1 copy of Wiretap, too, which is also quite a good card.
Pretty sure Goyo Guardian is going to be just like the other skills, in which it will be part of your extra deck along with 2x Jutte Fighter if you are using the skill, other wise the Jutte Fighters are not able to be collected and Goyo Guardian is part of some mini-box.
Watch his level up rewards be triple Assault Dog triple Handcuff Dragon triple Pursuit Chaser instead. With the level 23 card being Stygian Street Patrol and his level 30 card being Jutte Fighter.