I have a now aging version of acdsee installed here, and its primary use for me is for previewing images.
I can double click on an image file, and acdsee's image viewer opens, maximised, displaying the image. From there, I can use the scroll wheel to advance to the next image, or back to the previous image, I can double click on the previewed image, and it then shows me the containing folder, with that image selected, and from there, I could set some acdsee tags to it.
As I see it, MC really badly needs a way to view the big picture, set some tags, then move on to the next big picture, and so on, don't you think?
Doofs plugin idea, captionator, is the kind of thing I'm getting at. All that needs is access to tag info up the left-hand side and we'd be set, or maybe just a handful of select fields for use with images, or something...