I did complete a Masters degree which indeed assisted my goal of becoming a better doctoral program applicant. However, I was in the rare situation of having funding for my M.A program. If money is no object, you may wish to explore an MA first if you are not absolutely certain that you are committed to the professional and personal toll that such a committment brings about. Also, given the competitive nature of specific programs, you may wish to have this as an asset to help your application or to determine that this is not for you. I would argue that 50% of my MA cohort decided not to apply to Phd programs after completing the MA even though they came into the program feeling ostensibly certain of their doctoral aspirations. Thus, my advice would be to be completely cognizant of your committment level and goals and make application choices based upon this.