BW and BW-SEM - Separating landscapes

Hi,

We currently have a single landscape for both BW and BW-SEM running BW 3.1 and SEM 3.2.

Now we have been asked to looking into separting BW and SEM to separate landscapes.

We need advice/recommendations on whether they should stay together or be separated.

Any body went through similar decision making process?

If so what decision you made and why?

Best Regards

Srini