One major setback is that the modding tools, while helpful, are completely separate from one another. Ideally, there should be some sort of integrated toolset that pulls all these components together for faster workflow.
Another major setback is the nwscript language is very unreliable. I've had times where the difference between something working and not working comes down to literally nothing. Completely random.
Lastly, we can't and shouldn't be paid for doing this work, which, let's be honest, would be a pretty big incentive to stay invested in the work.