Personally to me most of the appeal of Maplestory is the 2D Side Scrolling style it has. Releasing MS2 would halve the small fanbase maplestory has here compared to in Korea which wont be good for money as then both games would have a smaller amount of people playing.
Im a new player (15) , and only recently heard of the big bang, and I have to say, I enjoy post big bang more and dont get people that complain. I still find it fun and addictive and the game looks much more beautiful than pre big bang from what I've seen in videos. Nostalgia can blind you from the bad the old you playing at the time probably found the game fustrating in some of its mechanics. The only real thing I'd probably agree with you on is Community. But thats expected when things get old, and then a new other fad comes along.