So, I still don't like the trade, but I do think there is a chance that Granlund can be better than he showed in Nashville.
For instance: his shooting percentage has basically stayed the same (around 8% for the Wild, and around 9% fo the Preds), but literally the moment he switched from the Wild to the Predators, his shot totals plummeted.
Shot totals his last three years with the Wild (81, 77 and 63 games played, respectively): 135, 124, 121
Shot total his first full year with the Preds: (63 games played): 94
Shot totals dropped even further from there.
Edit: the above numbers are all 5v5
That ~30 shot per season dropped right as he switched teams? That's almost certainly a reflection of a change in systems.
Granted, that still only translates to around 10 goals per season from him, which is not what you pay someone $5M per season for, but it at least shows that evaluating him based on his time with the Predators may not give a good view as to what he can do. There may have been a mismatch between player and system there.