Brian Silverman, one of the driving forces behind LCSI for decades, plus Turtle Art, LEGO TC Logo and even Scratch will tell ou that one of the problems with FOSS is that there is no mechanism for leaving out features - a critical design discipline when creating constructionist learning environments for children.
I wish Gary, Brian, and a chunk of the rest of the learning sciences and ed-tech research community would find the time to observe a successful open source community, like, say, the Python community. Sit through one of Guido's "State of the Python Union" talks, where he explains what changes will and will not be made to the language in upcoming versions, or peruse the mailing lists discussions or the Python Enhancement Proposal index. Simplicity and clean design is just as much a core principle in Python as it is in any learning environment for children, Guido strictly protects that simplicity, and it is one of the key factors in Python's established and growing success. There is absolutely nothing about open source software development that says it is a democracy. People will request things, whine and squawk, but the maintainer is free to ignore them.