As I know there is no throughput unlimited 3-2 balancers in the wiki. I'm not sure if this is really unlimited but that's what I have came up with (left):
So are there any pitfalls with this design?
Update:
I already found that its consumption is not even (right belt is consumed faster).
I just use a normal 4-4 balancer with an extra balancer on the end to reduce it to 2 belts output. Simple and always full throughput. Most other attempts at 3 belt balancers are throughput limited.