It's the classic combiner size conundrum. Combiners are explicitly shown in fiction to be much more than the sum of their components - literally, when it comes to size. Combiner bots clearly mass shift to a great degree when they combine. How else could you possibly have a bot that's smaller than Optimus or Megatron become an arm for a bot large enough to grab Optimus or Megatron in one hand?
Toys still have to obey the laws of physics, so there's no way to ever do a single version that matches proper scale as both individual bots and as the combiner. The best they can do IMO is to scale the individual bots, and engineer the combiners so they each generally scale with each other. I.e., basically what all the non-Titan PWT combiners, Legacy Menasor, and now SS86 Devastator have done. I think Titan sets like CW Devastator and PotP Predaking are the only way we'd get full-size combiners. (I'd actually love to get a full set of those too.)
These new ones definitely do seem to borrow a lot from the CW Constructicons in terms of design and aesthetic. Well, for the limbs at least. I think Hook and especially Long Haul are where we'll see just how substantial the differences are. As much as this new Bonecrusher looks bloated compared to CW, I expect Long Haul will look really slimmed down in comparison. It seems like they're trying to keep all the Constucticons about the same size, with the price class differences only covering differences in engineering and accessories. It seems the waist and thighs will be a separate component this time around, like the forearms. I'm still waiting to see how much of the torso is Hook & Long Haul, and how much might similarly be made from additional parts. I.e., how are the arms connecting, and what are they connecting to?