i guess AI sovereigns get to pick 2 paths. last game i defeated procipinee and markin and made them vassals and both had dual classes. the trait UI only showed one class, though. so the extra class they get to pick may actually just add its initial bonus (like +1 HP per level for defender)

EDIT: thinking of it some more, i think there is actually enough room in the UI for a third tab (for a second path)... maybe the devs were at some point (or are still) tinkering around with multiclassing? this could be a fun concept I think.

maybe halfway through your career (level 10 or something) you could get a special level up where you can pick a second path OR a unique extra perk for your original class (or maybe a large XP percentage boost perk)- so you have the option to specialize deeper in your original class or spread out and mix and match perks from two paths - I think that option could add a lot of fun and also some depth to the character development.

Do I pick the 40% XP boost and fill out the other half of my path of the warrior, or do i pick path of the defender to turn him into a juggernaut with both superior offense and defense - or combine my warrior damage perks with assassin crit perks to create the ultimate wrecking ball - or pick up path of the mage and turn him into some sort of spellsword/paladin with a mix of martial and magical abilities etc.