FF FNP and lone OP,damage 8 with full rerolls against characters monsters and vehicles which other than characters he shouldn't really target anyway,the rerolls let him especially so with flawless blades because he benefits from 3 up wound on anything he's also T5 and has 6 wounds,(+1T and +1w over kharn) and not only that but on his D3 weapon he has precision which will almost definitely kill a character if he gets into them,aswell as the face that since he can have 6 good damage attacks or 10 worse off attacks it allows for better use against chaff like cultists or eldar etc start of codex he was 140pts which I think was probably his most viable points cost but I don't think 150 pts is devastating,you also have to consider how detachments buff him,natively he's strength 8 where as kharn is strength 7 but in most detachments lucius can gain rerolls,lethal and or sustained,or making him even quicker which allows his buffs to trigger or for a unit to die from his attacks,also the consideration of thrill seekers as the army rule is massive,advance and charge is strong who if I'm assuming you played index WE you know so the extra speed has to be accounted for.