Informers are goings to be tricky to pin down and eradicate, so it makes sense they would be hard to target directly. I think the rules are working as intended - the Imani Pact need to buy an assets, expand influence, etc in order to become more effective. They're a insurgency so they need to start acting sneaky. Just because they're itching for a stand up fight doesn't mean they're ready for one.
I take the faction rules as being a nice base system ripe for expansion and modification to suit the needs of a particular game.
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