Looking back, only few were relevant.
Law is great, with significant fanbase in Japan
Kidd is....well he has 5 fans in this forum
Bonney only shows relevancy after Wano, but since she's linked with Vegapunk and Kuma she might have some supporting roles in the future
Meanwhile.....does Oda still remember Urouge?
What do u think?
Well leaving teach aside(for obvious reasons)I dont think it was a mistake but i definitely believe they should be fewer. Bege, hawkins and apoo were a mistake for sure. I mean not only they are weak but even their character is boring as hell. Killer is nice, shouldnt be a supernova though. I like his design and fighting style but just by his name you understand how much oda cares about him. Bonney is ok , urouge will play some role in the future and kid and law have been quite relevant so they all pass. Drake is the leader of sword and has much room for improvement so he pass as well.
So yes, they should be 3 less and killer should just be kid's vice captain and not a supernova.
Problem with the "supernovas were created they very last moment" info, is that we dont know in what extent is this true. Like maybe some of them would exist anyway, just not as part of the supernovas. But the notion that 9 different pirate crews arrived at the same time at the same place is so improbable that its basically just poor writing for me.
In the end, doent matter, the only major characters in the final saga will be luffy, teach, zoro, shanks, imu, dragon and maybe loki. All the others will inevitably receive the worgen treatment.