Nothing out game wise really justifies the extra money unless you just like having the new stuff.

Imo the 1070 is like the best bang for buck Gpu. Especially if you are coming from Console, anything is better than a console XD so i wouldnt be caught up in worrying about frames between the two, i doubt you will be able to really tell the difference between a 10 since anything will automatically seem better than what you were playing on before, hell even a 970 will be earth shattering for a console player. Personally i wouldn't go for the 2070, as someone who owns the 1070 i dont think the upgrade would be justified, the return in performance you will see is not worth the money over a 1070 imo. Only thing i really turn down is shadows and clouds because they are kinda pointless and unnoticeable for the performance cost.

Not just Dayz too, the setup will run just about anything you can throw at it that is optimized without any fear. Game runs butter smooth on extreme settings, dont think i can really recall bad frame drops or hitches in the game aside from server issues which is not fault of the PC. I have pretty much the exact setup you listed but 16GB of ram which i feel should be standard nowadays for gaming PCs.

How to make dayz run faster