I think this will make the forum far more useful. Could you add some kind of taglist (or prominent link to one) to the home page?
I also think this would be useful. Right now tags seem like a great feature for power users. But I feel that there is still the problem that people who are not yet engaged with EA and have specific interests may only see posts that are not relevant to them on the first visit to the forum and not come back. E.g., a biosecurity expert may not see any biosecurity posts and may not be interested in the three posts that they see after searching “biosecurity”. Having tags in a prominent place could help with that.
These things were discussed in more detail here.