"Loki can't join because he will replace Zoro/Sanji in M3/Wings."
"Loki is too strong for the crew."
"*insert random Wingtard excuse here*"
No matter who joins, it will always be Zoro and Sanji as the "Wings of the Pirate King"... And they are not such just because they are powerful but also because of their significance carrying Luffy on other aspects (logic, decision-making, etc.)...
If you are concerned about someone powerful joining, take the example of Jinbe... He permanently joined when Sanji was less powerful/capable than him... Same thing happened when Robin joined...
But let's focus with the Raid on Onigashima due to its recency...
1. Jinbe was matched against Who's Who because he's a cat and interested in Sun Pirates...
2. Sanji was supposed to be fighting Black Maria but due to his stubborn chivalry, he asked for a swap for Robin...
3. Sanji then faced Queen...
He is really meant to fight Queen, no matter what happens because that's how Oda wants it to be...
There were lots of incidents like that throughout the series... Enies Lobby arc was one of the prominent ones...
Something like that will happen regardless on who will join... He will fight the #3 guy available... Plot will create an excuse for the likes of Jinbe and Loki (you can insert Yamato if you want)...
Have faith in Oda... Have faith in being a Zorotard/Sanjitard/Wingtard...
"Loki is too strong for the crew."
"*insert random Wingtard excuse here*"
No matter who joins, it will always be Zoro and Sanji as the "Wings of the Pirate King"... And they are not such just because they are powerful but also because of their significance carrying Luffy on other aspects (logic, decision-making, etc.)...
If you are concerned about someone powerful joining, take the example of Jinbe... He permanently joined when Sanji was less powerful/capable than him... Same thing happened when Robin joined...
But let's focus with the Raid on Onigashima due to its recency...
1. Jinbe was matched against Who's Who because he's a cat and interested in Sun Pirates...
2. Sanji was supposed to be fighting Black Maria but due to his stubborn chivalry, he asked for a swap for Robin...
3. Sanji then faced Queen...
He is really meant to fight Queen, no matter what happens because that's how Oda wants it to be...
There were lots of incidents like that throughout the series... Enies Lobby arc was one of the prominent ones...
Something like that will happen regardless on who will join... He will fight the #3 guy available... Plot will create an excuse for the likes of Jinbe and Loki (you can insert Yamato if you want)...
Have faith in Oda... Have faith in being a Zorotard/Sanjitard/Wingtard...