I have been a phlebotomist for over eight years and have shadowed a PA where her only PCE was phlebotomy - we actually worked for the same company. So phlebotomy is definitely good as far as PCE. Where I work I do not just draw blood all day - much of my job includes training other phlebotomists, taking vitals, weight measurements and reading blood protein/hematocrit levels. There have been many times where donors go into reaction from blood draws or react to the anticoagulant fluid used to prevent blood clots. This can cause individuals to lose consciousness, vomit, sweat profusely, even convulse - In these cases I work along side other phlebs and nurses to administer IV fluids to help the donor recover. Having the opportunity to be the first responder in these situations has offered great patient care experience - in my opinion.
Having said all this, I have also spent 200+ hours working as a volunteer physical therapy aide for a sports medicine and orthopedic outpatient clinic to gain additional PCE. There is always room for more!