Lighting Blade and Dark Executor redesign

We all agree these two weapons look so damn beatiful, and we all agree that its a pitty to have them rendered useless? Cool.

My approach to the redesign is introducing a new feature to these two weapons. Double hits like bane, but instead of physical x2, a physical+magic damage combo. While keeping the +12 physical damage they already have during day/night.

For example:
LB would hit twice, physical damage + a lighting bolt
DE would hit twice, physical damage + a mass fire ball

I feel the actual STR requirement its ok with this feature. Lower STR could be too much.

Things to tackle:
1. Calibrating the magic damage. Would it be an already existing spell, or new ones? I think Lighting or Mass Lighting Arrow (single hit) spell would work for LB, but cant find a suitable one for DE. Mass fire strike is maybe too much, fire strike falls very short. BSW hit multiple times, also too much. 

2. Would it consume mana? Imo, it shouldn`t. Unless the magic damage is very heavy. Maybe a fraction of mana? Up for discussion.

3. Would MAG affect the magic damage, or should it be a fixed between certain values regardless MAG?

4. Should magic damage be considered elemental, with its penalties and benefits?

5. Should AMP/PFM negate/diminish the magic damage done?

6. Magic hit shouldnt brake paralyze. We already have spells that dont do it, so programming wise its doable? 

I think that this kind of feature could refresh a bit some pvp and pvm aspects. Besides, the visual aspect would look so good.

Maybe i`ll edit later with more of this, but for now, laying the basic idea and some questions for brainstorm.