In a way, bitcoin (and almost all other crypto coins) are still some what centralized. The devs are the centralization. There's not much we can do about that.

The redeeming thing is that almost all of them are open source with code available to be self-compiled.

If it were not check points, there is also the bootstrap file uploaded by Jeff Garzik. That is sort of centralized, but distributed by torrent, for all new users who need an initial sync of the correct block chain.

While the protocol itself is decentralized, it is a requirement that honest nodes form a consensus. Remember the hard fork early this year.