The barriers make sense to me. Having to support something just because it's there can become a significant problem and a high barrier to entry is one way to deal with that. You've probably already thought of this and dismissed it but coupling a high-barrier core project with a lower-barrier proving ground might be worth considering.

That's a shame. I explained my proposed patch when we discussed contribution without a facebook account in July 2014 so I'm a bit disappointed that it's been rejected at this stage.