NeilL,
The exact thing happened to me last August. It had rained the night before our attempt, maybe a quarter inch at the most. What I have heard refered to as the 'crux' of the climb, the waterfall, was as far as we got. There was quite alot of water going over it, and the only way around it is to jump left to right in front of it, then shimmy up the right side. All this while the falls are spraying you and the rocks. I was not comfortable with it, and there was no way in hell I was going to let my 12 yr. old son attempt it. Retreat was sounded with our health and our pride intact! And we never even got to the slabs.
We did go to the top from Lake Colden, where we passed a ranger coming down who had heard we were attempting the Dike, and she was very concerned for us. Needless to say, she was quite relieved that we did turn around.
Don't let a long distance view lull you into underestimating the hazards involved with a climb. Overanticipate the potential hazards you might run into so you're prepared for it. And by all means, DON'T be afraid to turn around!
Try the Dike someday, but do it in dry weather. Be safe!