I have noticed the exact same behavior throughout the BF1 lifespan. I think it just means there is a lot going on in the game that is not graphics related. Also the DX12 feature to reduce CPU utility is not making a difference. Dough when the system is flawless (no * in the back) it should run oké on you'r system as well. I never noticed a difference in performance for different game modes besides more ''action'' in a smaller area in Operations & Frontlines which is natural for these modes. I'm not expecting any change in game-engine architecture any time soon and expect it to be the same for future Dice / Frostbite engine games. I do wonder what CPU will only utilize for 50% in BF1 for a human price.
-My i7 4960X is on 97/100% all the time 🙂
-One thing you can try a few times is different Intel Chipset Software upgrades & Force GPU driver to do PhysX on the GPU (stock is auto mode)?