I'd like to be able to organize my caracters into major groups. I've been talked out of suggesting a "creatures" tab, the reason being another tab would pollute the design. I still wish, however, that I could separate actual character from creatures, and I think it could be done as currently PCs, NPCs, GM only PCs and GM only NPCs are separated: in a single page, grouped by headings.
Instead of "PC" and "GM only" flags in the character edit page, we'd have a "type" or "class" or whatever dropdown, with our groups. We'd be allowed to edit and reorder them, and have GM only be set on a group basis, with settings defaulting to the current "PC", "NPC", "GM only".