About transparent mining.. is it possible for an attacker to see which node is going to forge the next block, and DDoS attack it down? Maybe move on to the next one and then the next one and go on so long that the transparent mining becomes useless?
It's not possible yet. Later, when we switch from 4.25 tps to 1000 tps, forging nodes will be announcing gateways for incoming transactions. Anyway, these gateways will have ddos protection, so I don't think it's a big issue.