Tactics for playing as the Sylvan faction.

So, which third skill should I take (tactics or archery) since madness and rage are out of the question?

Ideally, you'd want to get "archery" and "retribution" (which comes through "BB"). But then you won't have empathy :( So, is it really ideal? :)
If there are no artifacts/abilities that boost speed, then "tactics" can be very useful. Also, elves like to close in and form a "box" when they have ents - "tactics" are useful here too. It all depends on the specific situation. But with "tactics" and "archery," we won't have either "retribution" or "rage"...