To my real point, I get that you're at least partially shitposting, but the advice you give is a) bad, because the problem isn't about running more-efficient Baneslayers, it's about developing an environment that can deal with mixed Baneslayer/Mulldrifters like
Mosswood Dreadknight or
Luminarch Aspirant and b) rudely phrased, in that you're implying that the problem is that I can't select "actual good" cards. I'd love to get your actual thoughts on the matter of how to deal with mixed Baneslayer/Mulldrifter threats that come with extra value efficiently without resorting to only playing strict Baneslayers like Arcanist or Goyf, but you're not exactly being helpful here.
I don't actually think the advice itself is bad, but I do fully agree that it is poorly phrased.
If the issue that you're having is that you need to be careful about which mulldrifter-y cards you're adding in order to avoid throwing off the balance, that's good! It just means you have a good handle on your environmental needs and can be selective about your includes.
If the issue is that you want to play better mulldrifters but can't, given the power level of your other cards, that just means that you need to adjust the power level of those other cards in order to align with where you want the new cards to be.
The big issue is that it's hard to give specific advice without analyzing the entire Cube when we're talking about environments like yours that work in more unique design spaces. One of the reasons why I don't try to give specific advice as much as I used to is because I realized that throwing out isn't really that useful unless I do the work to try and understand the inner workings of a given environment. Otherwise, I just don't think I'm going to have useful insights. But I think just generally saying: "make your baneslayers better to match the mulldrifters you want to play," isn't intrinsically a bad piece of advice, even if it's not necessarily helpful to your specific design goals.
I do think the specific example cards
@blacksmithy used were not the best choices as people see generically good cards and think: "Your cube is bad unless you play good cards," which is obviously not the case but could definitely be inferred with that sort of language. That said, I don't think the general sentiment of "adjust to what you want to play" is an unhelpful suggestion in a vacuum. Speaking from experience, this is often a good idea.
Hopefully this helps? Please let me know if I missed something. I definitely don't want to diminish your feelings because I think you are a genuinely thoughtful person who deserves a good answer.