I think programs like this are setting kids up for anxiety issues, giving up, etc. DD was in a program like this. The teachers claimed that it's not a problem to be "2e" (I asked ahead of time), but then they did very little to follow the 504, give her the structure she needed, etc. They gave 4th graders middle school work, but also expected them to have the EF ability of a middle schooler. Maybe many do, but many don't, esp. the 2e kids. It was the same sort of selection system--basically cognitive testing (and they add in reading/math achievement test results). I do think 2e kids should have access to gifted programs, but unfortuantely most programs do not seem to recognize the need to make modifications for these kids, and then the kids either flounder or get stuck in classrooms learning material they already know.(In our case we took DD out and put her in a school with "regular" kids but they cluster by ability, mixing up ages, so it ends up being a much better fit).
