One major issue in the game is that with all of the bonus content added it becomes impossible to have everything unlocked at level one hundred. You will be missing weapons, attachments, voices, gadgets, support items, fun facts, etc. That means basically you will be missing significant parts of everything except for aesthetic choices.
The newest announced paid DLC includes a new gadget and a new support item then also gives you a fun fact that’s sole purpose is immunity to the gadget and item.
The katana from the previous (free) DLC can be used to attain an almost game breaking endurance and in the priced DLC they introduce a support item (the conch) which can be used to turn the tables on katana users and is able to negate gadgets