David Huang and I hiked in here on our first day in Canada after a very long day in transit from NYC. This climb was one of the easiest I've done, really stepped out and never steep. Definitely more of a WI2 than a WI3 climb.
I rate Grotto Falls a WI 2, not a WI 3 as referenced in the guide book. I have not been on enough WI 2 to know what it really is, but I have been on enough WI 3 to know that Grotto does not fit that bill. The only steep portion I observed was the very first curtain, but even that is normally stepped and picked out by all the traffic. Grotto Falls is what it is, a good place to teach beginners.