twyacht, thanks for your reply.
During the video, the presenter had the same problem with the slide not removing freely as it should... and he just pushed "a little harder." During his re-assembly, I noticed that the guide rod on his pistol also extended beyound the slide's guide ring. He also stated that the recoil spring can be installed with either end toward the guide rod collar. That advice, however, contradicts the instruction manual that states the smaller diameter end should be installed closest to the collar.
I decided to try gentle tapping with a rubber-tipped hammer and off she came! Guess what I found... the recoil spring was installed backwards. My theory is that the larger diameter end of the recoil spring was actually slipping over the collar and binding in the frame's guide rod channel. This also explains the "floating" guide rod because once the collar slips into the body of the spring there is nothing to prevent it's movement forward.
Long story short - I think the problem was an incorrectly installed recoil spring. With the spring installed correctly, the slide goes on and off just like it's supposed to.
Thanks again.