FWIW, I have a friend who took 5.5 years to graduate from college because he only took 12 hours each semester. And it wasn't because he was working his way through school or had so many other activities going on. He just wanted to keep his grades as high as possible and his family could afford to pay our outrageous tuition for eleven semesters.
He graduated with a 4.0 and will be a FOURTH time reapplicant this cycle. Now, I'm not saying only having 12 hours per semester is keeping him out (LORs, essays, etc are more likely ruining him), but I know he has solid ECs and a 33 MCAT.
I personally question his ability to succeed in medical school because he hasn't learned to juggle. He always kept his course load as easy as possible and was still stressed. If I were an Adcom, this trend would make me wonder if the sheer volume of information would be too much for him.
I see the logic in protecting your GPA, but I wouldn't take it as far as this guy. Best learn to juggle now.
But I think you'll be fine for those two semesters.