That's a pretty extreme example, I'd say. I can't think of more than one or two weapons - or items in general, for all that - in 30+ years I've been DMing that have been anywhere near that complicated or fussy.
Well, what I'm trying to get at is that at one point in my DMing career, I got a great idea in my head for how to solve the problem that magic items in D&D didn't feel magical. They weren't mysterious, numinous, eclectic, dangerous, unpredictable, weirdness magnets the way that magic items tend to appear in fiction. And I think I actually worked out how to give magic items flavor, and starting implementing my 'great idea'.
And the problem was, that while my idea was achieving the flavor goals I set out to solve, mechanically it was just much too fussy. And in particular, the very idea that the magic item was mysterious and somewhat outside the player's control, even in situations where the item wasn't that complicated, meant that the player did not have full mechanical understanding of the item, which in turn meant that I the DM had to track all the information that the player didn't know and apply it to every scene. Like several of my 'good ideas', when I put it into practice, I found that I had to abandon it very early.
Still, one upshot of that experiment is that I often have very complicated magic items in my game. One of the swords in the party, an intelligent, legacy
+2 keen eager rapier of swiftness has a nearly page long description that makes the above item seem trivially simple. Fortunately, at this point, the player has unlocked enough of his weapons secrets that I'm happy to let him track the bookkeeping. Likewise, the
ancient monkey skull is a very complicated item with a two paragraph long description, that took the player about 4 levels of play and two years game time to figure out, but because it's a strictly command activated item, it placed no bookkeeping burden on me.
The biggest headaches, to be fair, are the ones where the character(s) think everything is known about an item but it still has something up its sleeve that their field-testing or ID spell just didn't (or couldn't) pull; as those are the ones the players just assume to be what they believe them to be. Most of the time if an item is unknown or uncertain the players remind me; a typical conversation might go like this:
Fighter's player: "I'm using this shortsword we just picked up. Roll to hit is 17 + 1 for strength, 1 for spec., and whatever the sword gives me."
Me-as-DM: "What item number is the sword?"
Player or treasurer: "147. I think it was in the mummy's coffin."
Me-as-DM if I remember what makes sword 147 tick: "Right, that one. You hit. Hard. Roll damage."
Me-as-DM if I don't remember sword 147: "147? Let me look that up... <<quick glance at my records>> ...right, that one. You hit. Hard. Roll damage."
Multiply the severity of that problem by like 30 and I think you'll see why the problem is not so much that you have to rework D&D to have numinous items, but that you have to do too much bookkeeping. Whereas, if there was some means by which the players dice roll was modified secretly and automatically and reported to me through a secure channel because the players character sheet understood what the items did even if the character's player did not, then what I was going for could work.
The only other way to achieve this goal I can think of is to have a rules light system where everything works according to the GM's whim, which then does make for mysterious magic, but in my opinion goes too much the other way and permanently removes the possibility of understanding by the player. At that point, the player is basically just along for the ride.
I usually don't have to look back very far as after each adventure they ID everything then divide and-or sell it. Again, it's only when they think they know one thing but the truth is another that I have to worry about it long-term, and even then only if they don't sell it. Those are the ones that generate sticky notes on the back of my DM screen.
I was in a situation where frequently, just sticking an object in your pack could have long term mechanical consequences. I try to avoid that now as much as possible.
Lan-"players forgetting to record item numbers with their characters' possessions (guilty!) also causes grief"-efan
In my game, if player's lose their notes on an item, they've also misplaced the item somewhere, likely never to recover it. Believe me when I say that this ensures the most meticulous record keeper in the party will in the long term be chosen as party treasurer and he'll be frequently audited.