I don't know much about weights but I don't think that theres anything in your programe for abdominals or for flexibility. I try to do some pilates exercises most days and have found it excellent for both. Because it can be done at different levels people of all ages and states of fitness can manage it. Theres a woman of seventy in a class I go to.
Unfortunately its often thought of as simply a form of exercise for women, this article might sell it to you
Pilates For Men
another quick google found this set of exercise on video. I think the abdominal one in particular could be a useful adition to your workout. Some of the other execises (eg arms) might be an alternative to the weights if they prove too difficult for your shoulder problem.
Pilates: How To Achieve Great Abdominals (Sports & Fitness: Pilates)
