I've heard that one casualty may be accelerating in math. Apparently the Common Core for math is that every year it builds on itself; it isn't in discrete topics anymore like Algebra I, Geometry, Algebra II, etc. So a gifted child can't accelerate through it.
With our local public school gifted program, my son will take Algebra I in 7th grade, Geometry in 8th grade, Algebra II in 9th, pre-calculus in 10th, then two years of Calculus. I'd hate to see that change.