Coppell was quoted recently as saying there was still a bit of a relegation hangover - I thought he was referring to Harps. I think Harper's time out is all for the good. It will turn his thinking from "whinge, moan, I should be playing for a premiership side" to "crap, if I don't watch it I won't even be playing for a championship one".
With respect to not changing a winning side - I think Coppell has been pretty consistent over the past few years- it's not changing the losing side that caused problems.