[EGreg]

Sure it can - it can just start reporting different things to different validators.

At this point the validators compare notes and gossip a proof that the node's been acting up. And then they need to elect another node, which requires... consensus!

Oh and the central node can also become unavailable and DDOSed, how are you going to add transactions to the ledger then?

[pfraze]

Choosing another node won't involve consensus in the way that consensus is described in distributed networks. You'd handle that ideally by a prior agreement -- eg, "if this node corrupts, it's going to go into arbitration via a trusted third party, who will then decide who will resume operating the network."

[wyldfire]

IMO this new design is "fine w/me" in the way that ethereum is "fine w/me." If people want a not-so-decentralized cryptocoin that's not-so-trustless, then so be it.

If it handles transactions faster, better, cheaper, and with less emissions, then so be it.

Unfortunately bitcoin's popularity/ubiquity makes it superior (for the time being) and hard to unseat. Other (decentralized) altcoins make really great improvements over bitcoin but never became (and perhaps never will become) as popular as bitcoin.