Not only is it boring and repetitive, it's also not viable. Sometimes, there just aren't enough looters to go around - and even if there are, you might simply not have the time to go bandit-hunting at the height of a war.
The perk itself looks like a milestone of army-leading, where you can now bypass bandit-farming for XP and instead just mass-recruit and fight big battles, where the mere passage of time allows your units to rank up while out on campaign. The fact that it doesn't work pretty much softlocks the player in the early game no matter how far they get. I am aware of the Looter auto-resolve, I have no trouble raising an elite army - but the fact that the perk doesn't work (nor the XP-increasing buildings in fiefs, for that matter) makes lategame unattainable.
Was just how i trained my troops since they wont get xp for much else, if i have them in combat vs big armies yes other wise nope, but hey. Its EA so i bet it will be tweaked

