What makes it so special?
Let me see... you mean beside the fact it is the most rigorously tested implementation out there maintained by a majority of the most recognized, experienced experts in the field?
Maybe but I don't see why it couldn't change.
It could! And I'm not against it but this is an especially hard problem because the pool of people competent enough to handle these consensus critical code is very, very small. To quote:
The centralization issue you refer to is nothing more than a lack of man power. That is, only a scarce amount of people are reliable and technically able enough to handle the highly fragile development of Bitcoin. It is no wonder the guys currently leading core are some of the world's most advanced experts in their own field. This expertise cannot be easily replaced or dismissed "because decentralization". It is absolutely unproductive and irresponsible to try to advance decentralization of Bitcoin development by encouraging incapable people to start messing around with their own implementations and risk breaking consensus.