1. This is a Harrison Bergeron argument. "We can't let people move quickly, because it might be unfair to other people." Effectively this means denying the people you can identify because there are going to be other 'deserving' people you don't identify. Replace 'education' with 'food' and see if this logic holds up: "We shouldn't feed the people we know are hungry, because other people might be hungry and now they would be disadvantaged because they would be more sickly and weak compared to the people we fed."
2. This is an argument that basically 'every kind of diversity is automatically good' or something. Dumb kids don't benefit from being around very gifted kids. They do see the very gifted kids and feel bad. The very gifted kids are going to isolate themselves from the dumb people as quickly as they can as soon as they can no matter what you do.
3. Smart people do well and often have smart children. They understand education because they have greater than average experience with education and a better ability to apply that knowledge. They will not stick around 'the worst schools' no matter how much you try to force them by handicapping smart kids. It's a free country, they will pull their kids out of bad schools. I think you'll find that parents are very uninterested in your theories of social engineering and much more interested in making sure their kids are given everything they need.
2. This is an argument that basically 'every kind of diversity is automatically good' or something. Dumb kids don't benefit from being around very gifted kids. They do see the very gifted kids and feel bad. The very gifted kids are going to isolate themselves from the dumb people as quickly as they can as soon as they can no matter what you do.
3. Smart people do well and often have smart children. They understand education because they have greater than average experience with education and a better ability to apply that knowledge. They will not stick around 'the worst schools' no matter how much you try to force them by handicapping smart kids. It's a free country, they will pull their kids out of bad schools. I think you'll find that parents are very uninterested in your theories of social engineering and much more interested in making sure their kids are given everything they need.