Since a rather sizable amount of RS2 has already been written using hash tables, it's likely this idea won't be accepted for it. implying axxo is doing anything right now hhhhhh
Regardless, either in RS2.1, RS3, or whatever it's going to be called, file based storage should be abandoned, and SQLite should be used. It's stabler, easier to manage using something like SQLite Administrator, and is compact and smooth. I've seen hash table files before -- it's hard to efficiently go through them because everything is randomly sorted for the sake of efficiency, and not readability. Not only that, but either the hash tables are unloaded and reloaded every time they're used (effectively canceling out any performance advantage), or the server has to be stopped before editing, then reloaded.
The only disadvantages I can think of would be that it would require another reset of assets, and if it were to be built on top of the existing RS2 scripts, harder to implement.