Ottawa plays, for lack of better words, a structurally dumb way of hockey. They have little to no structure defensively & most of their players are often erratic and make incredibly questionable decisions.
With respect to Dumba, who I'm sure could play a fantastic role for a team like Boston or a team full of high IQ players, would be awful here in Ottawa and would fit in perfectly with the rest of guys who make very dumb decisions that make you want to pull your hair out.
Trading assets + signing him to an extension would probably end in a nightmare situation for the Ottawa