Not really, I think... There are many situations where building level 7 creatures is simply not necessary for victory... For example, when the map size is 36x36... there are also many situations where you can manage without them...
Well, yes, you don't necessarily need to build Bone Dragons...
But I prefer to build them all.
My friend and I play Sylvan with 6 companions on KING difficulty on a generated map, and EVEN UNDER THESE CONDITIONS, WE BUILD THEM ALL!
