From my understanding: It's not "centralized". It's distributed. Just because the validators are known doesn't mean it's "centralized".
Distributed ledgers (the "permissioned" ones Tim Swanson is describing) are crytpographically verifiable.
Quite different from existing "centralised data-transmission systems".
I'm not an expert but pretty sure Eris Industries products (for example) are "working", you can use them right now.
Distributed =/= decentralised (can be but doesn't have to)
If you have to trust 'validator' and cannot enter the system as equal party, then such system is centralised.
I'm a bit tech-handicapped myself and I don't quite understand how such 'blockchain' would work, what would be incentive for participants and what would protect it from infinite-loops and bad actors. To my understanding, it has to be centralised, or be closed to any untrusted 3rd parties.
The author of the article (you quoted) clearly states that BTC blockchain and coinless-blockchains are very different ideas, and if the latter are successful they could only 'highjack' only part of BTC blockchain abilities.