Wonko the Sane
First Post
It would seem to me that high-crit weapons only add their bonus when actually used as a weapon, whether it be as a basic attack, or a power with the "Weapon" keyword.
If a +3 berserker scimitar is used as an implement by a 1st-level swordmage (18 Int) for lightning lure (Implement keyword), it would add +3 to attacks and damage rolls (Attack bonus +7, damage 1d6+7 lightning) and on a critical it would do 3d10 (berserker weapon critical)+13 lightning.
If the same weapon is used by the same character for greenflame blade (Weapon keyword), the attack bonus would be +9 (+4 Int, +2 Prof, +3 magic) and the damage would be 1d8+7 fire. On a critical, it would do 3d10 (berserker weapon) + 1d8 (high-crit weapon) + 15 fire.
Hope that makes sense.
If a +3 berserker scimitar is used as an implement by a 1st-level swordmage (18 Int) for lightning lure (Implement keyword), it would add +3 to attacks and damage rolls (Attack bonus +7, damage 1d6+7 lightning) and on a critical it would do 3d10 (berserker weapon critical)+13 lightning.
If the same weapon is used by the same character for greenflame blade (Weapon keyword), the attack bonus would be +9 (+4 Int, +2 Prof, +3 magic) and the damage would be 1d8+7 fire. On a critical, it would do 3d10 (berserker weapon) + 1d8 (high-crit weapon) + 15 fire.
PHB said:Accessories: These keywords identify items used with the power. If you have a proficiency bonus to attack rolls and damage rolls from your weapon or an enhancement bonus to your attack rolls and damage rolls from a magic weapon or an implement, you add that bonus when you use a power that has the associated keyword.
Hope that makes sense.