1911Tuner has commented on this topic more than once, and his comments are often received with some skepticism. Take it to the bank -- he knows this topic and 1911s.
When the slide is moving back, the recoil spring is slowing and slide, but so is the hammer spring. A heavier recoil spring, if it's not so powerful as to prevent cycling, will STORE more that force and when the slide slams forward, the extra force will have to be handled by the slide stop.
Depending on the gun's design, using a heavier recoil spring to protect the frame -- which it doesn't really do -- and could actually shorten the life of the slide stop. Think about it -- if the force being transferred by moving slide through the guide rod to the frame is so severe, why don't the bases of the guide rods get all messed up? Guide rods are typically made of less stout stuff than frames! Even plastic guide rods (CZs, Glocks, and other guns that use them), seem to hold up pretty well.
1911Tuner didn't mention it here, but here in his home state he has demonstrated that it's possible to fire a 1911 WITHOUT A RECOIL SPRING without ugly consequences; the gun fires and the recoil feels almost the same, but the gun just doesn't feed the next round.
Some folks who reload go to heavier recoil springs when they they see their spent cases being sent too far away (to easily recover). That seems to be a good reason to go to a heavier recoil spring.