The new marauders are a little larger than the old, but not awfully and personally, I put that down to them being hard ass Khorne guys who spend a lot of time in the gym when they aren't eating people. They do seem much better with regard to realistic hand size, etc.
Scale seems to be very random, depending on sculpts, with GW in any era. I have the old plastic goblins/night goblins that are literally massive. They're heads, hands, and weapons are too large for space marine bodies. Even the current Empire general on horse is a giant!