Luccis portrayal is very good. He did away with Sentoumaru - a strong man in his own right - easily. That in itself showed his threat level and Luffy acknowledged it by a) going to Gear 5 directly b) painting a target on his own back so Luffy doesn't go after the rest.
Lucci is most likely below King, who is a semi legendary fighter that has haxx, but surely above Queen who is a TERRIBLE fighter. Jack, Who's Who, Ulti, Apoo are all much better fighters than Queen. I'm not saying they would win against Queen because he has dinosaur skin, cyborg enhancements, plague weapons and lasers but his battle IQ is the worst of all commanders in the series.