I don't think you'll be seeing the mass registrations in the future. The Copyright Office has begun requesting that registrants issue a title of each work with collective submissions. I've got a feeling that it will become a rule in the not too distant future.
My largest collection was about 500 images, all submitted online, and took me several hours to complete. Adding a title to each image, and then adding the title into the collection titles will add quite a bit more work to the process. For me, it means that I'll probably keep my collective works submissions to somewhere between 200-300 images.
On the plus side, it'll take away any doubt about whether an image is registered or not and may cut down on frivolous litigation.
As for being worried that I'll anger a nutcase, not really. I don't send letters to "John/Jane Doe", I research the site/owner/ceo before I commence any action.