Mariners will have 2 big issues. Health and they need guys to play to their ability.
Morse is the health guy, when healthy Morse is a masher. Gutierrez is next on that list. If he can stay healthy and be the OK offensively and best defensive CF in baseball that's a huge plus.
For ability that is almost 100% Smoak. He needs to play like the top prospect he was. Maybe adding Morse to take the pressure off as top hitter will help but he needs to start hitting or he'll be relegated to bust status pretty quick. Montero is the other one but he's much younger than Smoak so he has some time before becoming a bust but still needs it.