Yes, a solution of fewer side characters would give the SHs more screen time. But I’m saying that there won’t be fewer side characters but rather complete opposite especially since we’re approaching the final war and so many characters will need to come back into the story and have their plot points resolved i.e. (the World Government, Revolutionaries, Blackbeard Pirates, the worst generation, the Wano cast, Zuneshia, Rocks, Imu, Grand Fleet, etc.).
Adding another SH would give the neglected SH members even less panel time than they otherwise would have gotten and should be getting especially since this is the Saga where the they would actually be achieving their dreams and every panel time with them in it will be important.
I wanted another SH for the longest time but I just don’t think it makes sense anymore especially this late into the story where panel time has never been more important. So I’ve made peace with it and moved on.