My wife bought a Glock 26 and had the same problem and now I carry it.
I have a Kimber Royal Carry which is slightly shorter than a commander length. I think part of your problem is not the stiff slide but the heavy spring that the shorter 1911’s need. You would probably start battering the frame if you went to lighter springs.
Take the gun apart and without the barrel or spring put the slide on and see if it’s really that stiff. I think you’ll find that it’s the spring and not just the slide.
I agree with Scott R, A woman can operate any slide on a 1911 if she does it in the right manner. Do a Google search on proper slide operation for the 1911 and you’ll see many suggestions. The following is a good one.
http://www.shootingillustrated.com/i...-manipulation/