I don't think it would be possible to make a meaningful, progressively sound and fulfilling game with Intersect atm. The base systems are very good, but I don't think without having access to things like combat formulas or experience rates you can make a wholesome game that you yourself understand fully. Things like balance and progression are hard to control at the moment due to not knowing how certain systems work and not being able to really learn about them without asking JC/Kibz or trial and error.
That being said, I think that with the source Intersect will probably be one of if not the best bases we've had for free 2D MMO making in years. Right now you could make something good, with the source you could make something great.