I thought they were all weighted? Maybe they changed the weight in relation to it's pivot point?
If I had to guess from how it feels, I would say the weight (the big triangular part) has been increased to add momentum to smooth the shift. That would be one way of counteracting the notchiness that you might introduce by shortening the throw. The weight is definitely changed in relation to the pivot, you can see looking at it.
Looking at some of the aftermarket parts, it looks like additional weight is part of the design. The APR adjustable short shifter for example has what they can ‘adjustable counterweights’ on it. ECS is similar.
I’m quite tempted to add additional weights to the arm to have a bit of a play. Nothing massive, but I bet you could feel another 20% in the shift. Obviously that would make getting out of gear slightly harder, but the payoff going into gear would be greater in terms of driving experience I would say.