I find it pretty disappointing that SICP is considered too tough for matriculants of a top CS program. Perhaps you should consider enrolling fewer students and raising standards.
Furthermore, I'm arguing that all things being equal, the time is better spent as a senior when you might be able to get the same points for a much lower time commitment.
And, please, remember that this is just one class in a curriculum of CS courses. There is a lot of effort being put in by dozens of professors to graduate the best and brightest, which we do.