It is not that Lucci is to weak, Luffy was just to strong. For other high tiers, Lucci would be a massive problem duo his attack power(lethal asf when even Sento got one shot even thought having haki on guard to defend himself) and insane speed.
He just mess with the wrong opponent, Luffy low diffed him without even trying out, Luffy was playing around and use base attacks, hit like two times Lucci seriously and Lucci was in glimps of KO...
If Luffy would be serious, G2 with adv CoC and adv CoA would be also enough. Lucci is not a match for him, Kaido and Luffy fight was a whole different league which guys like Lucci can't come even close at it, all hopes lies on Kizaru and im sure Kizaru will be crazy this arc.
For Lucci three possibilities(since he is back for the final clash):
1. Kizaru one shot him for what he did with Sentomaru.
2. Lucci face another strawhat(feel like Jinbe or Sanji) and get defeated complety later, but will also show a good fight not like how he was folded by Luffy.
3. He and the Cp0 escape without any big fight anymore.