Quote from: ProfMac on December 16, 2013, 07:57:13 PM

I don't understand how you think that checkpoints mean that a small group of people is deciding which branch is correct.

Checkpoints were put by small group of people, most of people even do not heard about checkpoints - and continue to think about Bitcoin as pure decentralized currency, while it is not.

Quote from: ProfMac on December 16, 2013, 07:57:13 PM

The protocol rules chose the correct branch. The checkpoints only document what that historical choice was.

Protocol rules allows to choose other branch if it has more accumulated difficulty, even if it is rooted in old blocks before checkpoints. Checkpoints override those rules - they essentially change protocol specification. By adding new checkpoint - you are forking protocol specification.
Choice of checkpoints should be done decentralized - by voting, and Bitcoin already has voting mechanism - vote by computing work. But if voting happens by hard checkpoints, selected by dozen of people - then it is centralized, with all bad sides of centralization.