At Wano there was tension. Protagonists being defeated.
The fact this is post Wano is what takes the tension away I guess. Wano was so bad it make post arcs worse than it should be.
I disagree. I dropped One Piece in Wano.
The only moment of tension, the defeat of MC was lost because of everything that happened after that:
1. Jail training didn't make any sence. Queen was able to kill Luffy in kairoseki cuffs;
2. O-Lin - is just the worst thing that ever happened in One Piece;
3. Defeat by Kaido wasn't the end, because Kaido was just one of 4 emperors. So the stakes wasn't even hight that time;
4. Wano arc as a whole makes zero sense, because Kaido was able to deal with all SH much earlier - this is what Imu is doing, which made Imu already a bigger treat that Kaido was, and not just from power lvl, but from his actions: he used Gunko as his vessal, than he teleported here himself, because he wanted to deal with SH once and for all;
5. The fight against Kaido started with Tension over 1000 and then dropped to tension -5000 because Scabards was cutting him like a bread, while before he was shown to be invincible.
6. Roof Piece was the moment that killed the last piece of tension because Luffy in base was able to stand against Kaido. After that moment, any unpredictable ending of the fight was impossible.