2. Communication Skills – Not only does a Marketing Manager have to maintain excellent communication within their own group and among his/her own vendors and suppliers, they often have to communicate plans, strategies, process and status to those outside the marketing dept.

3. Confidence- not sure if this qualifies as a soft skill or not, but a Marketing Manager usually has to juggle multiple projects. If he/she is overwhelmed by that, their group will notice it, and it will shake their confidence in the Marketing Manager as a leadership.

4. Natural Leadership – I think it’s true that leaders are born, not made. I think a good Marketing Manager exudes confidence, experience, and command of their subject.

5. Mentoring/Coaching Ability – A good manager learns what motivates their team members, and understands that not all team members are motivated by the same thing. Some team members just need a pat on the back, others are all about money and prestige. I think a good manager also has the ability to take people under their wing and "show them the ropes." This may be in terms of problem solving, working a piece of software, presenting an idea – whatever.

6. Natural Likeability – I think it’s always easier to work with people you like, and I’m a firm believer that you catch more flies with honey than you do with vinegar. Obviously, being a manager isn’t about being everyone’s best friend, but if a person is easy to get along with, able to keep stress out of the workplace, and leaves her/his personal problems at home, I think it makes for a better work environment.

These are the skills I expect from a supervisor and the one I I look for when hiring someone.
References :

1. communication
2. team building
3. team player
4. motivation
5. ability to develop and maintain professional relationships
Most of these fall under the large category of communication.

A marketing manager may actually use more of these than any of the hard skills I can thing of.
References :
15 years in HR having hired marketing managers and staff