Update - Disconnects and Latency Issues

I'm not saying to make it so it saves every second, but honestly thats one of the two ways to even stop duping in general. That+item IDs

I'm assuming that 5 minutes was determined to be optimal in terms of cost & efficiency considerations, so I don't think they can/want to change that. It's actually pretty decent, I wouldn't expect it to be much lower than that anyway. Not for the massive amount of data getting saved.

I think they will eventually realize that they need to address duping head-on. Item IDs need to happen

Not actually true.
It doesn't have to save every second either, just every transaction, and it needs to handle every transaction as a discrete unit, not individual parts that can be interrupted.

If it did that it wouldn't have to save every second, or every transaction, it could save on quit and not risk duping anything, it'd just risk data loss, not data duplication. That's the entire point of ACID design.

My only concern here is that this would involve a complete re-design of the save system. While this method is far superior to the current, it isn't very achievable (considering how much Nexon LOVES change).

The Item IDs, while still a major revamp, would seem to be easier to implement. I don't think any other major issues (besides duping) arise from the current save method. Aside from the fact that it doesn't make sense from a logical perspective, I think the current method doesn't raise so many concerns that it'd be worth scrapping altogether.

It's pretty fascinating how the game has never actually gotten a major structural overhaul, considering how old it is.