just got an idea for solving the first one
the error should be caused by calculating weapon proficency and by the fighters weapon talent. now, when using a weapon as an implement you won't add weapon prof bonus. and fighters will rarley use an implement.
what could easily be done would first to switch the implements weap prof sign to false and than wrap the weapon talent calc within enclosed WHEN's like WHEN(Class="Fighter";WHEN(...); ). Now you could as a swordmage create to attack bonuses, one selecting the specific weapon, one just with "light and heavy blades". use the appropriated for your power. since implement-powers (as fas as i remember) usually have their own weapon dice, this problem would be solved as well.
This way, only upon multiclassing swordmage with fighter or using an implement power weapon specific dice damage would result in an error that could easily dealt with by overriding the values.
just a thought, may be it helped, if not just ignore it
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