I don't know about the others, but Water 7-Enies Lobby showcases Sanji at it's finest and made many people favorite him.
1. Little to none simp mode or pervert mode Sanji.
- However, the love letter is pardoned because it has actual narrative function.
2. He gets to give great advice and quote, to Luffy Chopper and Usopp.
- He is shown to quickly react to Luffy's flub and doesn't mind straight up kicking him.
- He shows a gentleman mode to Chopper.
- He recovers Usopp's self-worth.
3. We get to see Spy Sanji or Tactical Sanji with the Sea Train scenes.
- Spying a high class Intelligence department is a good feat.
- This also cements Sanji as a Spy/Stealth type, a dynamic he can share with both Nami and Robin.
4. We get to see Swordman Sanji and know he has good enough blade skills.
- This is also a feat of Cook Sanji.
5. We get to see Fighter Sanji whose opponent doesn't have huge gap in strength from Zoro's.
- Also shows a battle that is balanced around both brain and brawl, Sanji's thematic ability.
6. We get a powerup
- It's explanation is reasonable, it made sense scientifically.
- The powerup can connect to his status as a Cook.
- The powerup also is not out of the blue or conflict with his principles.
- Whereas in WCI, Raid Suit isn't related to cooking and it antagonize his heart.
7. We get to see Hero Sanji / Savior Sanji with the big brain move of closing Gate of Justice, both saving everyone and destroys enemy at the same time.
Bonus point, we get to see a gag ability of Sanji to make someone handsome.
Also, a character is better written if you give him weakness and flaw, and you write around that. This arc accentuate Sanji's flaw: can't attack at range (this way Usopp is talked by him to do it) and can't hit woman (that's why Nami fights in his place).
This arc hypes him so much, his subsequent contributions in later arcs is just pale in comparison or just straight up heavily discounted.
1. Little to none simp mode or pervert mode Sanji.
- However, the love letter is pardoned because it has actual narrative function.
2. He gets to give great advice and quote, to Luffy Chopper and Usopp.
- He is shown to quickly react to Luffy's flub and doesn't mind straight up kicking him.
- He shows a gentleman mode to Chopper.
- He recovers Usopp's self-worth.
3. We get to see Spy Sanji or Tactical Sanji with the Sea Train scenes.
- Spying a high class Intelligence department is a good feat.
- This also cements Sanji as a Spy/Stealth type, a dynamic he can share with both Nami and Robin.
4. We get to see Swordman Sanji and know he has good enough blade skills.
- This is also a feat of Cook Sanji.
5. We get to see Fighter Sanji whose opponent doesn't have huge gap in strength from Zoro's.
- Also shows a battle that is balanced around both brain and brawl, Sanji's thematic ability.
6. We get a powerup
- It's explanation is reasonable, it made sense scientifically.
- The powerup can connect to his status as a Cook.
- The powerup also is not out of the blue or conflict with his principles.
- Whereas in WCI, Raid Suit isn't related to cooking and it antagonize his heart.
7. We get to see Hero Sanji / Savior Sanji with the big brain move of closing Gate of Justice, both saving everyone and destroys enemy at the same time.
Bonus point, we get to see a gag ability of Sanji to make someone handsome.
Also, a character is better written if you give him weakness and flaw, and you write around that. This arc accentuate Sanji's flaw: can't attack at range (this way Usopp is talked by him to do it) and can't hit woman (that's why Nami fights in his place).
This arc hypes him so much, his subsequent contributions in later arcs is just pale in comparison or just straight up heavily discounted.