in my opinion the key is in "who can run a lightning node/hub?" as long as it is anybody who wants (which is the case and now there is incentive to run a node) then i don't see any kind of centralization in this.
what's the incentive? how much can you expect to make in fees? i guess it matters how well-connected your node is. you have to weigh that incentive against the risk of keeping your private keys online too.
but the good thing that i understand about LN is that the relaying nodes don't know about the origin and destination of the transactions they receive, they just pass it along and know it doesn't belong to them.
indeed. i do like the idea of private, off-chain transactions. that's definitely one of the appeals of LN for me.