Qlasher here, just some comments...
The AI are way lower that when the server started up in August. There are fewer ai through the removal of randomly spawned ai. Today ai spawn with the random supply crate (2 ai typically), with missions (# depends on difficulty) and as zombies.
They are still very challenging and seem harder than other servers I have played on. In particular, suppressors have less benefit than I recall on other servers. There used to be sub-settings (not the right word) for ai difficulty settings in the epoch server I admin'd.
Definitely difficult even for seasoned players. I do believe that something on the Tanoa server is deterring players from staying. It might just be the continual low population and not enough join to cause other people to join.