You're right, Lvl 1 Focus is useless but what's the percentage by which ImmoWep damage will be increased anyway if it starts off with 1 Dmg? Not dramatic I believe.
Note that I'm not completely sure if Empowerment does anything to Immo. Forgot to try it without.. LOL.
Corpse Skin + Empowerment + Lvl 4-5 Focus.. I would use it if I were a Necro/Weave warrior with a very good Fireball weapon but then again most people run around with Corpseskin-proof armour.
Does Corpse Skin lower resistances even MORE with Empo to bypass those uber suits? In general I wonder what kind of effects Empo will have on Chiv, Ninja, Samurai and Necro(Thinks Omen + Empowerment).
Another question is this : Which is the best order by which to cast spells to fully benefit from the increases of Spellweave?
Empowerment -> Focus -> Empowerment -> Spell or doesn't the Focus itself become more potent if it is created under the effects of Empo? LOL
Oh well. If they ever do look into Weaving I hope they make most of those buff spells targettable so we can buff up friendlies! I'd love it if Essence of Wind etc were also like Wildfire, AOE in targetted area instead of like Wither.