I find that most things people look at in movies to not make sense actually did and they merely think it doesn't to inflate their ego.
Case in point is the sword. It makes sense that the guy didn't know of it because he never had it in the original. If he had it back then he and his brothers would have used the fuck out of that sword. Instead he had to resort to using improvised weapons until he was outright told "you have a badass sword now". Mako knew about it because she didn't take a multiple year break and knew of the upgrades. Even if you point out that he was drifted with mako they were still at that time using things he already was used to. Ever not remembered something until a person said something else? That kinda happened for Mako since it wasn't at the forefront of her mind until her partner actually thought he was out of stuff. She remembered.thought about it, the drift made the guy realize he had a sword and they immediately went for it.
The drifting doesn't seem to dig into the deepest memories. it seems to go into whatever you're thinking of at the forefront. Mako's little episode was because she kept on thinking about Tokyo. You've gotta be at least halfway thinking about what you want to share first. Ergo sword doesn't get noticed until mako is wondering why he hasn't somehow noticed the giant sword he has.
It made perfect sense in terms of you have a damned giant robot. Go kill some monsters. Anything leftover that can be found via nitpicking like the monsters not actually being able to exist in rl goes into you're overthinking it.