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I'm with you did,
I don't like that kind of waggle as part of an actual swing. But I think our kid uses it more as a pre-swing thing, sometimes WAY before the swing, than as part of the actual cut. He certainly does that in the homer video and in many of the BP swings he doesn't use it at all.
In this clip from HS it was a major part of his actual cut, he started the bat from the waggled position. https://www.youtube.com/watch?v=MT0jNxLVot0
It existed in some form here in '13, as well:
https://www.youtube.com/watch?v=MWq5yNrpYsg
It looks (to me) like he's reduced the waggle and uses it more as a pre-swing key now.