I think there are some serious problems regarding developing this game.
First:
The big elephant in the room. Many of W:A players, deep inside think that this game belongs to history and it can't compete with today's inductry anymore. They look at this game as a nostalgia, like a NES game and that's it. To compete in today's industry, you need at least a better looking game. 256-color palette won't cut it.
Second:
I think this game has gone into a non-creative lazy mod. My wife's dad calls it mind masturbation. It's an state of mind where you are full of great ideas, you get excited with endless possibilities (you get a mind-orgasm). After that you are really not in the mood to DO any of those. It was just your imagination, no real life motivation. That's where 4.0 stands.
Third:
Team17, W:A developers, TUS and people who can change it are NOT united.
Team17's position on this game is obvious. It is an abandoned game, hence its developers are not important enough. W:A developers doesn't like that attitude. They are also not in need of the "community money". You go one level lower and there is TUS. TUS is an individual project grown with the help of the community. To many W:A elders, after 6 years of serving the community, it is still an impolite kid sticking out his tongue at them.
An example is, TUS hosts over 10,000 BIT maps. It would a nice addition to Hosting Buddy. People could load BIT maps by giving TUS Map ID. This idea has been rejected. (not going into details)
In brief, each party does improvements as they see fit for themselves in their own time-table.