Other than for legacy reasons (peercoin's coinage stuff), was there any reason for keeping the nTime field in transactions, and referencing the txPrevTime (rather than just txPrevHash) in PoSv3? I've been analyzing the consensus rules around the transaction nTime and it seems to add a lot of restrictions and potential attack vectors, but for no obvious benefit. Can you share any insight into that?
It should be possible to remove nTime from transaction. I didn't go that deep because of compatibility reasons.
Yes, It would make blk compatible with vast big field of bitcoin software that is available now, BlackCoin should be able to use blocktime in staking and remove nTime altogether.
Maybe in POS 4.0?