1: Bulk uploading, especially when it comes in this late in the game.
2: Easier tagging. Seriously, I just uploaded 18 pages of comics and I had to write the tags out manually on each of them. Just let me copy/paste the repeaters, or something!
3: Tag memory. Keep a list of tags I've used recently, so I can easily just click on them to add them.
4: Comic navigation (pooling) - Not sure if it has this or not, couldn't see it while uploading at least.

I'm sure I'll think of something else as I upload the remaining 30 comic pages.. >_>

Edit: Found one. Default journal rating to General instead of blank.
Edit 2: Oop, found another.. Avatars in the messages list, so I can visually tell people apart. You'd think that one would be a given..
Edit 3: The ability to create folders DURING submitting something, rather than having to leave the submission screen, create the folder and THEN submit to it.
Edit 4: The ability to full view an image without having it open OUTSIDE of the site UI..?