Open source generally builds slowly. It takes time for communities to coalesce around new tech in ways that are meaningful. It is worth the effort and time it takes to keep the software updated.

For faster feedback on the core ideas, a paper would serve very well. You'll have the attention of your peers and the faculty to gather initial impressions.

There isn't any reason why you couldn't do both. Open sourcing new ideas doesn't mean you cannot write a paper on the subject. The code is still your idea at the core. Refinement of the code doesn't change that fact.