Magazine Scans:
https://imgur.com/a/Le8SO8h
He says it's unusual for a romcom to not have a clear main girl
Cites Toradora and Meizon Ikkoku as iconic romcoms with clear main girls
Negi likes manga that make you want to talk to other people about, have debates over who is cuter
He wanted to make such a manga himself so he thought about what is necessary and unnecessary
The unnecessary part was "an ending where the MC is connected to everyone", that's why he put the wedding at the beginning
To avoid people saying "first girl wins" he introduced all the girls in the first chapter 
However the editor made him introduce Itsuki first (and have her in the centre in the Vol 1 cover) to make it easier for readers
Negi thinks if people liked Raiha or the classmates too much it'd create too much noise so he gave Raiha a weird hairstyle, but it turned out too cute in the anime
He's dissappointed that there are still people who expect a harem ending after he made it clear there's only one bride
The interviewer says things never go exactly as planned and fans just don't want to see any of the girls rejected
Negi is grateful for that but says that because works with predetermined heroines are getting popular lately he thinks series like Ichigo 100% actually feel fresh to today's generation
Interviewer asks about Fuutarou not being able to tell them apart despite having different hairstyles
Negi says he only had the hair colours be slightly different for chapter one but thinking about a future anime adaptation he thought it'd be hard on viewers so in the end he gave them different hairstyles AND hair colours
He made them all redheads because he thought it would guarantee popularity
The interviewer calls the different hair colours a necessary lie
He notes that the flow of the story, the characters and their personalities are all intricately thought out and that there is a lot of drama
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