Firstly after reading this whole thread, I can understand that both sides of this debate has some good points that need to be addressed by NCSOFT. However from personal experience from this game and others, unfortunately I'm going to have to side more towards being against an anti-cheat in this game.
Here's why...
1) I used to be a player of a popular Korean-developed 1st person shooter game called Alliance of Valiant Arms which got published to EU/NA region just like BnS has (sadly the game got shut down in July 2019 due to licensing issues, but is in the process of redevelopment and is soon to be re-released). You maybe thinking how is this relevant? Well let me tell you. This game used to use XIGNCODE3 as it's anti-cheat, that was one of the major flaws for it. It would ban random players for the dumbest sh*t, and over half of the bans or account flags that it gave to players were false-positives. Did it stop cheaters? No, absolutely not... It was getting a higher percentage of 100% legitimate players banned from the game than actual cheaters, any cheater with half a brain was able to bypass it as there were loads of individual coders with separate bypassing and cheat methods for the game, making it almost undetectable. My biggest worry and concern is the same happening to Blade and Soul, where it is mostly innocent players being caught in the crossfire of this with a shoddy anti-cheat being to blame. Also with how this anti-cheat worked it would ban players through the anti-cheat itself, not through the publisher, meaning if someone did get banned they would have to appeal it to XIGNCODE3 instead of the game's support team, which the XIGNCODE3 team never responded to tickets for, meaning all those innocent players who did get caught in this trap never got to play on their accounts again. Saying this, it wasn't totally impossible to "unban yourself", since at the time it would either IP-Ban or HWID-Ban a user, both of which an individual who knows what they are doing can essentially change their system files, to make it look like they are playing from a different machine or from a different IP, rendering this banning method useless for actual cheating players (again harming innocent players). If they are to actually add an anti-cheat system, it needs to have NCWEST in FULL CONTROL of it and understand the difference between what is malicious and what isn't, so even if there are false-positives, it can be looked into by the support team here and dealt with accordingly.
2) Most of the edits to the game files that the community are using is for Quality of Life purposes which has previously been stated clearly earlier in this thread in which should be added to the game itself as features/options that can be toggled on/off in the game by a player at anytime they wish. Let me give you a few examples of Quality of Life edits which makes this game so much nicer to play, which does not alter the gameplay or give an individual a particular "advantage":
-World Lighting Removal (This made it easier to see boss attacks, such as the red/purple/yellow markers on the floor, currently without it, it can be very difficult to see this on any current in-game graphics setting, especially in certain areas of the game)
-Less Loading Screens (Most of the time the loading screens are pointless and is ultimately time-wasting, this basically helps a player be able to actually play the game instead of being forced to watch a stuck screen while everyone else with faster pc's are already clearing a dungeon being impatient to wait for your butt to load in)
-Cutscene Removal (I understand that a lot of effort went into making these cutscenes, but my strong belief is that after a character has viewed this cutscene atleast once, they should be allowed to have an option within the settings to permanently skip the cutscenes from triggering, as again this wastes a lot of time and can be annoying, sometimes killing a player if they are gliding/jumping over a spot where you can fall to your death is a cutscene triggers by another player at that exact moment, such as in Cathedra Cliffs or Shadowmoor)
-Skill Rebinding/Relayering/Simple Mode edits (I understand this can be considered "controversial" depending on the desired outcome, but honestly despite the negative points against this, I still think the positives of having this as a feature in the game outweighs the downsides to them. This adds a lot of playability to a great deal of classes and specs, especially when "simple mode" is tuned a lot better on some classes/specs than others, so allowing this gives a player freedom to decide what they want it to do, putting everyone on a more even playing field, fairer overall. Those of you who just say "learn your class" over being able to rebind/relayer/edit simple mode is simply not a good enough argument in my opinion. Why? In certain situations FPS can be really low and can be difficult to trigger skills properly to get cooldowns from gear to proc correctly/do proper rotations, not only making someone with a worse pc/connection at a major disadvantage, but completely making their class/spec unplayable; this is more noticeable on Soul Fighter and Assassin from personal experience. Whereas with the ability to use Simple Mode and edits to what skill goes where on your keyboard, it counteracts this, allowing someone with a worse pc to do just as well as someone with an expensive high-end pc.)
-Instant box opening/transmutes (Honestly without this, the game feels sluggish and can be annoying to sit there for AGES, just for completely pointless countdown timers to trigger something that can be done right away. If the ability to use this gets taken away, I personally would feel very annoyed as this has to be one of the biggest QoL improvement that the game needs.)
-DPS Meter - So you can see top 3 DPS in your party in a dungeon/top 6 DPS in raids (I personally love this and cannot understand why it is currently limited by default to just your own DPS... It's nice to be able to see what other players you are playing with are capable of doing so you can use it to improve your own gameplay)
-There are more that I can cover but the ones listed above I would consider to be actual proper Quality of Life changes that should be added to the game by default without the need of modifying game files to do so.
3) At the end of the day, I believe that when it comes to the use of "modified game files" such as addons/XMLs etc, it should be used with common sense. By this I mean, to use it purely for improving the quality of the game itself and NOT using it to abuse in PvP/Leaderboard content. I'm personally all-for people being able to use these 3rd party tools as long as it's not used to gain a significant advantage over another player that is playing without them, such as for ranking rewards on leaderboards or in PvP/Clan Battles for example.
So yeah, my point still stands, common sense and courtesy to other players in a "competitive environment" is important above all else. They only become a major problem when it is used in such a manner.
TL;DR
-Anti-Cheat needs to only be a thing if NCWEST is in full control of it and can understand the difference between malicious intent and simple QoL changes etc.
-XIGNCODE3 is known to cause false-positive cases, catching out and banning far more innocent players than actual cheaters.
-QoL 3rd Party tools should be added to the game by default as features without the need to modify the game files.
-Common sense and courtesy is important... do not use cheats/3rd party assistance against other players for personal gain such as ranking rewards on leaderboards or in PvP aspects of the game.