> But FLOSS software is mainly made by developers. Who like writing new flashy features, but are awful at UX, and making sure all the small kinks are worked out.

That is what product managers are for; someone to lead the product's direction, ensure quality control, and to instill taste. That requires being able to say when a feature is poorly implemented or outright bad and unnecessary -- it's not always just kinks. The problem is that this collides with the collaborative ethos of open source software. But when it's not done it's the users who suffer.