Regarding a option to turn digger zombies on/off
I think it would be a very small amount of players who would turn them on and then the developers would have to entice the player to use that option with a special unique loot or something else rewarding which could be counterproductive.
I mean if you have that checkbox there how many times are you going to try tactics compared to if it was not an option ?
Also if you where to reward the player then you could just turn them off untill you built or aquired all your countermeasures and then turn them on again.
Just my idea, opinion, and I don't even know if it is even doable, but when we start the game we have the option to pick scavenger, warrior, insane and whatever the other levels are. Could it be made that in the higher levels the setting would be to have the more challenging and dangerous zombies? The irradiated cop, and I think there is one that is a feral, then the irradiated feral wight (or whatever it is called), and other zombies that are really hard to kill could be in those levels. Allow players have the option to try that out, the experienced players can have the challenges. Those who are casual, weekend players can chose to try out the warrior one, or one of the other choices that might have a setting where they get the cops and wight on horde night, or at any time.
That way everyone gets what they prefer.
I agree that rewarding the player could encourage players who would be going "I don't know if I want to fight that" will go "Yes! I'll give it a go".
Right now the irradiated cops, feral wights and some others have no loot at all, many of the zombies have lousy loot. I'm grounded again on my shoulder, so my fix is watching a variety players on youtube. Some I see as great, GameEdged, Kage848 who I watch all the time, Games4Kickz some of the time and also Veudi (I know I spelled your name wrong, sorry) he has a play style that I also enjoy so I watch him a lot, forgot to add Flexible Games, I watch him often. Some others are good, some okay, some so lousy that I won't watch them again.
The small amount of players is the problem in whether or not TFPs decide to leave them out, or to add them and have them for when you get a really high game level. Those who want such a challenge should have that challenge. I'm not against it, it's fun to watch them play and fight those zombies. I don't want to, I am a coward in that way, but I like to see others show their expertise and they should not be limited to because others don't want to face them and/or loose all the work they have done on their underground base and see it collapse.
If players chose to turn the option off and not play with diggers on (or the more deadly, dangerous ones), then I go that is their choice, and their lose of some good loot.
Just my two cents