Let's ignore the G5/G4 talk and approach this a bit differently. You say, "Luffy
had to use G5 to beat Lucci." For Luffy to
need G5 to beat Lucci, at least one of these conditions must hold true:
- Lucci's awakening is OP enough to rival Luffy's—a foolish assumption to make given how Luffy's fruit is God-tier while Lucci's fruit is 3rd-tier.
- Lucci's Haki is as good as Luffy's—another bold assumption as even top-tiers aren't known to possess level 3 CoA.
- Lucci's base physical stats are so much better than Luffy's that it helps him close the gap created by Luffy's Haki and awakening—Luffy's base stats are equal to Kid, a physical monster that could hold his own against Big Mom at least in a brief fight.
I am not even including CoC here. You guys are giving way too much credit to Lucci. As for the whole YC1 talk, Luffy exhausted 2 rounds of G4 and needed to learn FS to defeat a YC1 that half contributed to his own defeat. And this guy was a glass canon among the YC1s. If Lucci can't touch Luffy's most vulnerable form in his best shape and form, good luck ever touching Katakuri, forget about merking him. Marco could legit exhaust Lucci without ever using an offensive move against him lmao. One Jackpot is all it takes for King to end Lucci's entire career—his half-assed Haki wouldn't even protect him from the blast. Let him get past Jack in endurance before we can talk about him merking the YC1s.