I seem to recall a lot of the pre-IR hype, that IR would never change the way the game was officiated, just improve the results of decisions that may have been made without benefit of the best angle or unobstructed view. It would just improve the accuracy of close plays.
What's the actual result been? Yes it has increased accuracy on close plays, down to the gnat's eyelash or blade of grass. It most certainly has affected officiating with revised mechanics dictating when and how to rule on certain circumstances to avoid limiting the capabilities of IR.
There are three levels of participants in this game; coaches, players and officials. Where once human error was accepted as possible from any of those three, the required unbiased, instantaneous decision making of officials is regularly called into question and second guessed. Suggesting that doesn't undermine the decision making process that has been so critical to the success of the game is naive.
This inhuman requirement for precision is slowly creeping into the players participation in the game as well. Minute, even microscopic stop action review is being used to determine precise responsibility for helmet contacts, which are being judged more by slow motion review than by human judgment of competent, highly trained and skilled observers assessing intent, which for generations had been the primary deciding factor whether a "foul" had occurred.
This is a game involving 22 people moving in multiple directions within a relatively close proximity often colliding with significant force and much of deciding what they do, when they do and how they collide has always considered intent as a key factor. Circumstances dictate the movement and where speed and ferocity are key attributes, precision of that movement has always been an acceptable casualty, as viewed and judged by other humans trained and skilled in observing movement to judge intent.
Coaches are not excluded from the added precision of today's technically advanced reviews, as they are subject to far more second guessing supported by gnat's eyelash slow motion by self impressed armchair generals who may never have been any closer to a playing surface than their couch. Absolutely, IR greatly improves the precision of judgments, but whether it advances the game is another question.