I have not seen anyone state that focusing on smaller players is a sound primary strategy for drafting; rather, I believe the primary strategy in these situations is drafting skill. The same could be said for focusing on players just because they are big - not a good strategy.
I would like to see this data which describes the correlation between size and production; however, I would bet that it pales in comparison to the strong positive correlation between SKILL and point production.
Correlation does not always equal causation. Success in the NHL is dependent on many more variables than just size or skill.