Game Design: Bonesword

As Warhammer 40k 8th edition came out I was surprised by the quality of the rules and how many of the historical problems of the game were sorted out. Yet the designers at Games Workshop found themselves in front of a tricky challenge, translating all the rules of the game into the new system, a task that inevitably introduced many flows, imperfections, and negligence into the game.
Now, it's worth notice, without questioning the reasonability of such situation, that months after the release of 8th edition, many of this problems are still in the game. In the videogame industry, it would be impossible to leave such design mistakes inside a game months after the release, but the wargaming community and the Warhammer community, in particular, grew a particular mix of patience, love, and Stockholm syndrome for Games Workshop, that allowed GW to gate rules behind a paywall without curating them too much. But I don't want to talk about how harmful this is to the players and how possibly this can backfire tremendously right in GW's face in a near future; what I want to do now is taking one needle from the haystack, take a closer look to it, and put it back even deeper in the haystack. And let's be clear, I don't do this because I don't like the game, but, as good old Jim Sterling often say, I do this because I really like the game and I want only the best for it, and of course, to possibly inspire a conversation on the topic
The needle in question has more the shape of a sword, a Genestealer Cult Bonesword in particular, that stood out to me so much, that I may even write something about it on my blog... Ah! Yeah... (so meta!). Just a little introduction to the whole deal: in W40k, models, and every single piece of equipment that they bring in the battle, have a price point so that all the armies that are worth, let's say, 1000 points are all balanced. This also means that if a single weapon or model has a "wrong" price point attached to it, it will result positively or negatively unbalanced. For the same reason, buffs and nerfs come in the form of price variations.
The Bonesword, well, it is indeed unbalanced, but in such a perfect way that it became a good example of bad game designing, something to learn from; as it hides way more problems than what stands out at first sight. So, starting from the top I'll deep dive into a deeper-than-expected analysis of this weapon.

Some Vixel Art I did about Genestealer Cults, I really like their style!

What is the Bonesword? It's a sword designed to penetrate armors more efficiently than other basic weapons available for the Genestealer Cults (GSC). One of the underlying themes of the GSC is their powerful but expensive armory, that it's in high contrast with their low resistance, creating the typical and unique mix of high risk / high reward at the base of the GSC design. The Bonesword fits into this mindset and as such, is very expensive.
So, if it's expensive is also powerful? No, and here lay the problem, it's not only weaker than its pair in other armies, but it even contradicts another underlying theme of the GSC: the base weapons are stronger than average. The HAND, called Rending Claw, of some of the basic units of the GSC is as strong as a special weapon in another army. When GSC pick a special weapon, this weapon usually costs even twice as much as the model using it, but it goes from an autogun to a giant mining laser, from the rending claw to a Heavy Rock Cutter, literally a giant scissor able to cut enemies in half; the jump is notable. The Bonesword instead have the price of a powerful weapon but the stat of a basic weapon, it doesn't know where it belongs.
But how bad is the situation? The Mathammer is a tool used by many players of W40k to crunch some math around the game and come up with wrong answers. Even if this is a math-heavy game when things are in motions on the table everything behave very differently, as models are in cover or out of sight, you need to move losing accuracy or you simply die before even shooting. The Mathammer is useful to solve some of the problems around the game, not all of them. Fortunately for us, the Mathammer is perfect to solve the math around the Bonesword, as in this situation we are asked to choose between Rending Claw or Bonesword, the first is free, the second is relatively expensive. Both weapons are going to be used against the same kind of target in the same real-life scenario, the weapons are so similar that whatever weapon it’s picked, the playstyle will not change, so at this point what's left is to do some Mathammering to come out with the right weapon to use.
And which one is better? Now we get to the meaty stuff: because the Mathammer tells us to use the Bonesword, designed to penetrate armor, against targets without armor like Guardsmen, and instead use the rending claw, that completely ignores armors but only on lucky rolls, against armored targets like Space Marines. This is highly counterintuitive and clear only after some math, I'll go back to this later.
Who uses the Bone Sword? The answer to this question makes everything even worse. Firstly the weapon can be chosen by the Hybrid Metamorphs, the worst unit in the game, that happens to be a GSC unit too! They are not worth considering and I don't want to spend time on them as they disappeared from the game with 8th edition. More importantly, Acolyte Hybrids, one of the two base units of the GSC can pick the Bonesword, but to do so they have to trash their dagger, that happens to be another really powerful basic weapon, granting a bonus attack to the bearer, so even if they happen to be in the situation where the Bonesword is useful, the little margin granted by the Bonesword is not enough to justify losing one attack, resulting in the (expensive) Bonesword to be actually a nerf for them. And finally, the biggest problems rely on the Primus, one of the leaders of the GSC. The model has a Bonesword in a great display, as such, it is considered part of the mandatory equipment for this model, not an option. The problem is that the Primus already as one of the best weapons in the whole game, a Toxin Claw, a power-up from the standard Rending Claw (is like a hand full of sharp edges and venom dripping everywhere). The Mathammer will easily confirm that there are no situations where the Bonesword is stronger. So the player is forced to pay the points for the Bonesword of the Primus even if it is literally a useless weapon.
Ok, let's talk game design now. Now that the picture is clear, let's go deeper into the implications of all these factors combined together. Starting from the Primus. The idea is that the model has the Bonesword, and it's not an option inside the plastic kit, in these kinds of situations weapons get rightfully integrated as part of the mandatory equipment of a model. Let's suppose that the designers at Games Workshop did the math and realize that the Bonesword is useless on the Primus, at this point, as happened in many other instances in the game, the price of the Bonesword is removed from the price of the Primus, so: (Primus - Bonesword) + Bonesword = Primus. In the eyes of the designers, the Bonesword is given for free to the Primus and the price match the one initially intended, everything works and it gets packed inside hundreds copy of the rules around the world without realizing one huge problem: the players will see the Primus from a completely different perspective, being able only to see the final version, what they see is: Primus + Bonesword = Primus + wasted points. This happens because the price of the primus is the discounted price, not the original one, and the Bonesword is just adding over it. A design trick to fix the points may be perceived in the wrong way by the players.

My first Neophyte with a custom color scheme.

But what about the "fantasy" behind the Bone Sword? The player is granted the ability to pick a weapon that has a slightly better armor penetration than the base weapon, to no surprise the player will pick this weapon and use it against armored targets. Now, as said before, this instinctive behavior from the player will lead to the wrong result. Weapons should follow a fantasy, and rules should match the idea behind a weapon. Going against this principles lead to very dangerous territories. How can the designer expect a new player to learn how to play if the game is counterintuitive, and even more, if the designer gives the option to pay points to get a weapon, how the player should understand that the right thing to do is to ignore this option completely? Such players that pick the Bonesword are objectively lowering their chance to win. The devil's advocate would say that players learn to play by doing mistakes, but this mistakes should come naturally during the game, not artificially insert in the game by the designers. What lesson there is here to learn for the player? To not trust the game's rules, to interpret rules? Indeed the W40k helped to coin the term RAI (Rules As Intended) trying to interpret the rules of the game "as they should be", useless to say how harmful of a situation this is. And how it harms the competitive community that is rising around the game.
Now, what if a new player glues a Bonesword to a model to only later realize the error he/she did? In that moment of disappointment, would the player be invited to keep playing the game or rather leave the game? It would be interesting to ask the designers how they ended up introducing this trap inside the game. When players ask for the rules to be free, it's not just from an economic point of view, if the rules were openly accessible, even the designers would have the needed freedom to fix problems that are hurting the game.
So, how would I fix the Bonesword? The idea would be to give an option to the player, not something that they always have to pick, but if they pick it, it's mostly helpful: I would call it Cult Bonesword, to differentiate it from other Boneswords around the game, making it unique to the GSC, it would cost a couple of points and it would keep the bonus attack from the cultist knife. This is just one of the possibilities. How would you change it?