Sure, but you've got to start somewhere! And with the amount of progress I was able to make in just a few weeks, I'm very optimistic that the polish will come sooner rather than later.
i'm curious if you intend to reimplement highly optimized numerical algorithms, symbolic algorithms, and so on, accumulated and tuned in mathematica since its 1988 release?
it's a huuuuuuuuge amount of technology in the standard library of mathematica, beyond the surface syntax and rewrite system, i mean.
Based on the list of contributors to your project, I am not sure this starting location is optimally suited to the task of building a foundation for polished, reliable, expandable software.