passive mode is a choice in the current system,

passive = not able to act quickly, hp regen mp regen increased movement speed
active = able to act instantly, tp drains more slowly

you choose what you want based on what you plan to do. if you want to recover you go to passive, if you want to keep killing you go active. Games generally do need obstructions, and choices. Its a descion you make based on the circumstances. The time required to sheathe and unsheathe is part of the advantage to staying in active mode, while you are active you are ready to attack instantly, while you are passive you are not, and are focused on travel, or resting.

I understand you prefer that choice didnt exist, but it makes sense in terms of game design, and game rules for balanced choices.

dont fret though, i think they said they will make the animation faster, and may allow you to do it while moving so you may get what you want.