No we don't. What we might conclude if Young/Valencia started is that he's resting his players for the CL, or that he's gone into his big game shell again. They went after him for him Zaha and Fabio, look at how they're performing now. What's the guarantee that an inconsistent half-fit Nani, who hasn't played for ages, will do a better job than Young, if Januzaj/Kagawa were to be rested for the Greeks?
I'm not rooting for Young to start, I'm saying that if that happens, it doesn't necessarily mean Moyes doesn't want an attacking side. There will be many sticks to beat the manager with if we see another disappointing lineup, but your theory is not one of them.