I too would vote that avoiding the skip doesn't necessarily avoid the problem. My older brother was never academically strong (I now wonder - a lot - about what he could teach us about our 2E children if anyone in my family could admit there was anything to talk about). I was never skipped - but I was doing my brother's homework before I even started school, my friends were always of his grade not mine, my marks were better even though I did no work, and I compressed high school to graduate at the same time he did.... children are incredibly aware of the differences among classmates, never mind among siblings. To this day, to my great sadness, this incredibly creative and intelligent man considers himself the uniquely not-smart member of a smart family. Accelerating me wouldn't have made this dynamic any worse (but would have improved my lot considerably).
Instead, give each kid what they really need. And pay a lot of attention to their unique strengths and weaknesses, so each gets the support they specifically need, AND the room to fly where they were made to. Celebrate the differences, let them each be proud of themselves and of each other's unique accomplishments, rather than make both kids feel like they are wrong to be who they are.
Oops, sorry about the soapbox. I just don't think this kind of sibling problem is solved by pretending it isn't there - which is really all avoiding acceleration does.
