I agree.
Previously an imgur album link would show the title, a preview of a images in the album, with controls to cycle through the images in the album, and the current image comments below. I think at a minimum the imgur onebox should display the title and the number of images in the album to let the reader know they should go to imgur if they want to see the full contents of the album.
I’d really like to be able to cycle through images in the album within Discourse, but I can understand that may be a lot of work to add if the imgur onebox is now custom code within discourse instead of just using imgur’s scripts.