Lol, speaking of which, Constantine's The Wolf doesn't have Werewolf tag. I imagine his other builds won't be tagged as well 

Unless a host adds the tags for him. Constantine isn't on the blog very much anymore.

So tempted to change my user name right now...

Half the point of the tag system is that we don't have to do any work. We're not tagging other people's builds for them.

He should have!  I mean every skill in a game can have almost absolutely corresponding tag for it except Alteration. Adding it will make Mage and Elementalist categories less cluttered and will be fair to Tolfdir! 

Remind me, should the tagging system fit the theme of a build or the skillset based upon TES class system? For example, should Vilkas be a Knight,  Barbarian or Warrior if he was a tagged build?

It is up to the build creator and what they think is more important.

Some of the tags describe skill sets pretty well (Blacksmith and Alchemist jump to mind), but are not from the TES class system (at least not as far as I remember). Other tags fit the TES class system overtly, but the skill set is not as well defined due to changes between titles or skills having been removed from Skyrim.

If I were tagging Vilkas, I would probably go with Warrior and Werewolf, but someone else might find other tags more important.

Thanks for clearing that up Greyson!