Ok, just read six pages of discussions on the iPhone. Big headache now. Better go to sleep. I only suggestion is that if you suspect the fault is at the camera, then sell it and get a new one. It's really your choice. Disappointment is not going to fix the issue.
Check out the manual on page 326. The second paragraph talks about direct AF point selection. I have mine configured so I don't have to press the AF point selection button to use the multicontroller to move the AF point.
I would recommend you to read the following article. I personally have stopped using RAW + JPEG. I think it is a waste of time and space.
I agree with other comments. Replace continuous lighting with strobes. It will make a big difference. Also remember to keep the subject away from the background. Shoot in manual mode in RAW format. Then just keep shooting.
Thank you for your comments. I do not normally convert my photos to black and white. The color version was just awful due to non-controllable lighting. I started to realize that one way to recover a bad photo is simply converted it to B&W which can hide some major flaws.
It's about the quality of the photos and how these photos are presented to the viewers. I believe you should also have a purpose for displaying your photos. It could be for marketing or sales, or a simply way to share your work with friends and family.