That is a perfectly reasonable argument, but I am not sure that the Cub roster lends itself to filling the 3rd spot in the batting order, unless you use ARam there, and then have no good option for the cleanup slot.
I'd use Ramirez there, and I think Pena would be fine in the cleanup slot. Or, if Pena can hit .230-.240, he'd be fine in the 3rd spot.
The best solution might be to use Soto there on the days he plays. Getting his OBP that high in the lineup would be big. Other than foot speed, he's a perfect fit.