Nitpick: I don't think there's anything wrong with a closed development model and open sourcing the result, but IMO it's not open source until the code is available. If you're starting a project with this intention, I don't think it's really Open Source until your first code dump is publicly accessible - at which point, go nuts with branding it Open Source.

I also don't think it's unfair to do code dumps, if the code is available then job done. Other projects provide additional hand holding, but in my opinion that's a feature that the original authors have the freedom to choose to not implement.

I'm really pleased that Mozilla have chosen an open development model.