Category types
editConcerned mainly with categorization. Category links are now being used to represent a variety of semantic relationships. I think the proposal at Wikipedia:Category_types breaks down the different category types correctly, and I think this scheme can be employed without affecting the "power" or "expressiveness" (if you want to call it that or something similar) of the categorization system as is. This proposal says nothing about requiring a category type, so people that do care about this information can pay attention and those who don't, don't have to.
More generally, I feel that the categorization system, as is, has become so muddled as to simply not be terribly effective at helping me, or anyone else, find information. More categories and category links do not necessarily improve the usefulness of the system, especially with no distinction whatsoever between the different relationships represented, or more appropriately, no ability to distinguish if one so pleases.
I think the above proposal goes a long way towards a saner, more useful system.