Yeah, but only 7 feet? Hand Clap not only has the knock down (at least it's knock down for me because I put a KB to KD in mine) but it also has a nice stun effect. It's the Fault of Super Strength. And if we moved it to T8, what use would it serve at this point? It's the same exact power, no suggested changes, you simply lose out on your best damage mitigator in the set in place for a smaller radius knock down, that also does not stun. So in one hand, you make a power better, but you utterly kill the other power and make it pointless to put in to the build.
Now, if you wanted to make Hand Clap do AoE (perhaps a small DoT?) Damage, make it require a target, and give it range (much like Fault has Range) and THEN move it to T8, I think that would completely justify the change and the move to T8 with Hand Clap.