Well, Lugar and Darkshine Knight's MT techs are unreasonable, because currently, they can combo. I know you're still brainstorming about the combo issue, so this is just one way resolve that issue, although it depends on how much they are nerfed.
It would also affect the MT techs they can cast whenever they feel like it, so those two issues aren't 100% related.
I'm taking ideas for that; could e.g. just reduce the atk to 75% its usual value.
E.g. vanilla is for 300 atk:
300 x2.5 - def = 750 - def, so at least 450
300 x0.75 x2.5 - def = 562 - def, so 262 at max def
or maybe only 7/8 penalty
300 x7/8 x2.5 - def = 655 - def, so 355 at max def
And Shadowzero... Those are just so so deadly. Unreasonably deadly. They need to be nerfed, I feel.
They copy 1:1 the stats of whoever they copy. The only thing they don't copy is spells known.