I don't know if this is a concern or perhaps a bonus, but I do know that github encourages a lot of forking and hacking and contributions from coders on the "sideline". This may also produce some interested hackers creating unique changes that might not otherwise have happened - also because primarily it's something they get to put on their github page as "popular repositories" and "contributions" within the last 6 months. I know there is some software out there I've contributed to that was on github that I might not have contributed had it not been on there, because they make PRs really really easy.
As an aside, I get the warm and fuzzies when I hear "Inkscape is already insanely popular" even though I had nothing to do with it. It's great software, you guys are great. Keep it up!