I might swap out extend for martial feat. It depends on how much I fight. I use a +wis longsword for my fvs a lot and then I don't fight. I just destruct things and need the extra bonus to DC. I swap to my superior potency item when I need to heal. You can still wear an item you're not proficient with. You just get -4 to hit. At high level I should not have to fight.

Originally I would want to swap Extend for Spell penetration or Spell focus evocation