Hmm.
I like the idea of giving the bandit lord invisible spies ... maybe giving spies to an Assassin/Rogue lord as well?
(aka the assassin profession for Sov, which is different than path of the assassin, or at least I thought it was)
I think that'd be cool imho. Two factions that deal in spy networks (basically a small hidden scout unit with 0 attack ... maybe a trait that adds move and vision, yet makes one unable to enter tactical battles? (would get booted out of one, even if defending in a city. honestly I think ALL 0 attack units should do this, since the AI won't use pioneers as meat shields in combat anyways). And how fun is it really when an enemy archer kills your Noble Lady just because you don't have archers yet? They'd tell zero units to 'stay back, stay out of the fight' as its basically women and children by that point.
So anyways, invisible scouts. As we can See INSIDE of enemy cities already, the only advantage is that ppl cannot see that they are being spied upon (and obviously they cannot attack what they cannot see).
-> I think if an army initiates combat with a stack of ALL zero units, it should do an Automatic Autoresolve for a complete win with zero mana lost.
-> however people cannot see the invisible spy, so they cannot attack him.
This would allow some real flexibility in information gathering for those two professions ... would be pretty fun! 
Perhaps the Assassin profesion's difference is that it focuses on making the Sov stronger, while the "Bandit Lord" focuses more on mundane unit recruitment.
----> Maybe rename Bandit lord to Mob Boss or Mafia lord? Otherwise yea, just allow the Bandit lord to focus more on 'mercenary buys' as in buying new units with gold instead of resources and time.