So right now, I currently have all of my swordsman gear at 4 stars
-Ash Tail Cap
-Ash Tail Coat
-Dark Thorn Shield
-Dark Thorn Blade
-Avenger
-Gigawatt Pulsar
-Freezing Atomizer
At this point, how should I go about upgrading my gear? Do I go for the Vog Cub/Coat recipes with the Barb Thorn Shield for its bonuses, or should I focus on getting a Divine Avenger for a significantly improved charge attack and a Shivermist Buster for a much greater freeze radius?
Ordinarily I'd tell you to upgrade your weapons, because play on Tier 3 is less about armor absorbing damage than it is about dodging and killing monsters. However, you currently have no elemental or fire protection, so maybe you should get one piece of Vog Cub soon. And your armor/shield will give improved damage bonuses when they're upgraded. It would help to know how many weapons you carry at a time.
Really there is no bad plan here, but if you want a concrete recommendation I'd say (A) get one piece Vog Cub, then (B) upgrade your two swords, then (C) get one piece Skolver and Barbarous Thorn Shield, and then (D) upgrade the rest of your weapons.
P.S. Somewhere out there is the Acheron or Gran Faust of your dreams.