Beeing stuck with the BF2 engine is what IMO kills the mod. If there is no hope for overcoming the limits of the current engine and therefore never see anything really new except for 3d content, would suck the motivation out of me if I was a developter.
The mod may live on for a couple of years with a small player base as it is, but it will finally die. And then all the blood and thears that have been spilled while creating all those nice 3d models will go to waste. I must admit that I start loosing interest myself, because I know that nothing really new will happen. Even a eastern front or a pacific front will have crappy driving physics and all the other problems of the engine.
I say it is time to push out a last good release that can be played for a while, pack all the models and textures into suitcases and then choose the best suited open source engine and port the game to it. Then the game might even draw new players and developers. With full controll over the engine, implementing new things will only be limited by the lack of manpower.
Maybe even I will roll up my sleves and help with fitting the target engine to our needs. I at least would take a look at the source code.