MapleStory's Future

It's not the client that needs rewriting, it's the server.
Or rather, the relationship between them.
The problem with MapleStory is that it was apparently written as a mostly peer-to-peer game, with the server doing extremely minimal duty as switchboard. With time, the server took on more functionality, but the clients still do a lot of the work that, logically, should have been in the server. And the server lazily accepts whatever the client says is happening, without question, not realizing that the client is "in enemy hands", on the user's computer, and can be made to say whatever the user wants it to.

This is what needs to change, the basic architecture, if we don't want to see new hacks appear with every new skill or event. And this is what I can't see Nexon putting effort into. They'd much rather create fancier sprites for old and new skills (while still not fixing memory leaks and other fundamental flaws, which obviously makes the game laggier and glitchier with every new version), add worse bosses and then more OP classes to fight them and then revamp the old classes to balance with the new, and so on ad nauseam.

One can only hope that MapleStory 2.0 will have a saner architecture.

I see. Well, actually, my biggest hope is that they will change the current game's architecture in better. Let's hope for that, even if unlikely. They are more likely, as you said, to make MapleStory 2's much better than the current one, and to leave the current game intact.

If I recall, big bang WAS the rewrite? I'm not sure I just remember that being the case

I doubt. The main client-server structure didn't change, nor did they fix the main issues with the client itself. They just revamped the server's code to make it better for THEM to add new-content and manage everything, but it doesn't seem they changed the main thing (and maybe the most difficult one) which they should have changed: how the communication between client and server works.

I don't agree with just making a new game to revamp the old one. They just need, as sapta said, rebuild the architecture.

I agree with you. Or, at least, if they really want to make a new game and they plan to let the current one go, then they should allow dedicated players to somehow "transfer" their characters (and their work) to this new game, even if it's REALLY, REALLY unlikely that'll happen.