I say brace height.I don't like really short a-a bows,because of peep alignment,and excessive nock pinching with loops.They do seem to be less forgiving than longer a-a bows.Finger shooters like longer bows,with higher brace heights.So they don't pinch their fingers as bad,and higher brace heights are more forgiving.The increase in height along with the shortening of the bow is probably because the limbs are parallel,and more laid back because of riser design.It will also help the bows accuracy,as I have found that short bows are not as forgiving,but the increased BH helps regain alot of that,. have not seen the bow you speak of,I'm just guessing.

So I say 1-Brace height
2-a-a length
3-riser design.

Hope I helped.