From comparison pics, its more obvious that the air intakes are big and don't jive very well to the whole fighter package and lacks the sleekness.
Looking at the side profile of the SV-51 posted by Vic Macini, the SV-51 has a pretty long gullet. And also notice the difference with the yamato. The intakes on the topview lineart show that the intakes don't start from where the canards are, but its a top-cover. The intakes start abit further back away from the canards below the cover, as can be seen from the side profile.
The yamato however, there isn't this top-cover. Right after the canards, the intakes are there. But this is also the case for the hasegawa. Hmmm. Well anyway, its apparent now that the legs/intakes are abit bigger then they should be. Not sure if they could fix this without compromising transformation.