I've said it before, but I think the biggest move he could do, is take a year off from developing what we have currently. Instead spend that time on working with a few guys from the community on developing the use of things like HDR environments, Move to a PBR instead of a specular workflow, Dynamic lighting/shadows, Post-processing effects(Motion blur, Depth of field, Ambient occlusion, Bloom, etc.), Erode development, and probably most importantly, optimizations. After completing a few of the above listed he could very easily release the game as MX Simulator 2, and with the right promotion, I believe there would be a massive amount of sales.
I can't speak for others, but I would be more than happy to help make all of those things possible, for an extremely reasonable price. The only reason I still contribute to the game is because I love seeing how far we can push this thing. I personally wouldn't even ask for anything up front.
I don't believe that JLV needs to hire any additional coders. From what I have seen, he appears to be more than capable of achieving what I have listed, code-wise. This wouldn't really be any different than how some things have been implemented into the game. JLV gets an extremely good base code down and then has had select people test it and work on it together. Take terrain normal maps for example. If I'm not mistaken, DJ worked with JLV on it before it was officially released to the community.
I don't think we will ever get to a point where JLV would want to commit to working with people on creating models. From what I understand from talking to people who have worked on major titles, licensing isn't the easiest to get. That's probably better left as it is currently. However he could get people to create generic models and gear.