Tag spamming is very bad for you
Currently, there are too many posts that are tag-spamming to get as wide a reach as possible. As a result, the tags have a low signal-to-noise ratio. It's hard enough to get your content seen by people as it is, the tags on the right are almost useless. I want the photography tag to be lots of pictures, the introduceyourself tag to show new people.
If the tag system is kept, I would propose that there be some sort of penalty for tagging a post with more than a single category. Currently, there's no incentive to curb tag-spamming and that just reduces the utility of tags in general.