This is wonderful. If we could combine the visual ease of Worldcat's version with the intellectual depth of your version, we'd have something really useful. Having grown up in the card catalog era, I'll always prefer the alphabetical list, but the utility and intuitiveness of the word cloud is clear. I just wish the Worldcat version didn't contain so much duplication (same concept in other words). It just goes to show that our subject heading system is broken.
I'm glad you like it. It's not too bad. I also like the alphabetical order, but it just doesn't work for people today.
One thing that could improve in the Poe version I gave is that all of the subdivisions of subdivisions could be handled better, e.g. all of the Criticism and interpretation subdivisions. Maybe it could display just once and when you clicked on it, you would see the subdivisions somehow, or all of the subdivisions of Knowledge. But I don't know. It does seem to me to be a step in the right direction, and would certainly have more impact on the public than the changes that RDA intends to implement.