I would reduce the sugar by 1/3rd, not peel the apples and use whole wheat flour.
Actually, I make crisp with whole oats instead of flour, and just add, brown sugar, cinnamon and butter. My grandchildren call it, "Grammie Crisp"...it's one of their favorites.
I have always tried, and so have my children, to make food as healthy as possible. Obesity (35lbs overweight) is a disease that 38% (I think) of Americans suffer from. I know that over half of us are overweight. It can lead to diabetes, osteoarthritis, heart disease, (even children are being diagnosed with diabetes and high blood pressure))...not fun things to have. Now if I could just stop at one serving.....LOL!
Oops sorry....off my soapbox now....