I thought programmers would be the easiest...we're actually going to finish the buttpiles of art before the programming, at this rate.
The problem is probably that:
1) Most game programmers usually have their own ideas and want to develop their own games, even if it could be sometimes more beneficial to cooperate.
2) There are a lot of (usually over ambitious) game projects offered by so-called 'game-designers' that obviously aren't going to take off, so a lot of developers have a developed a built-in suspicion towards them. Maybe I'm just talking for myself here, though

So it's probably difficult to just motivate good developers for a project like this.
But the most difficult thing with a gaming project is probably finding artists doing the graphics, and setting realistic goals. And that's exactly what you seem to have nailed here. A princess-maker-like game is certainly not an unrealistic goal.
That's why I'm for once quite positive about this proposition, so I'd like to urge any proficient java developer in here to consider this.
Just some questions though:
Do you have any specific roles for developers lined out? Do you already have a developer?