I don't think we should eliminate tags. PeakD allows 10 which is a little excessive. Actifit allows something like 20 which is plain stupid and hive.blog allows 8 which seems about right.
Random initiatives can be tagged in hidden comments the post to award it (ex. pinmapple).
Tags should be used based entirely on the topic and content of the post. For example if you don't mention the word in the post at least once or twice, why is it being tagged?
It's been made fun of a lot and people don't even care because so many people tag so poorly. I am personally trying to improve, but I still tag the odd irrelevant thing.