I don't really market weddings but I shoot about six a year and second shoot a bunch. I believe it is really important to be versatile as a photographer. You must learn all aspects of photography and never stop learning. I have noticed that most "wedding photographers" don't know how to track a subject and usually only shoot in Manual Mode.
I have a question for Manual Mode shooters: What happens when your subject, "bride and groom", go from inside the church to outside, but they happen to kiss really quickly in the doorway outside and continue moving? I can tell you... you overexpose the photo. I shoot portraits and posed shots in Manual but the rest of the wedding in Aperture Priority mode with back button focus in Al Servo. This allows me to track the moving subjects while at the same time creating amazing portraits. You must have the shutter speed at over 250 to freeze the action while the bride and groom are walking down the aisle. I personally think for tac sharp photos it must be above 500 for this type of photography. For sports I believe it is 1000, call me crazy but this is from my personal experience.