With the last event forcing me to use Magneto (Modern) I have come to realize he is the perfect battery for Storm (Classic). With his ability to add 5 blue tiles to the board allowing you to select exactly where to place them, I think we need more characters that have similar abilities to become batteries. I think Thor is one of the best Green tile batteries but the cost of his ability is 12 where mags is only 9.
Mags is one of the most efficient but if other characters had that exact same type of function we’d get complaints of no diversity. As it stands we have quite a few batteries with varying approaches:
Doom (blue->black), Grey Suit Widow (purple->green), Hulk (green), Marvel Now Mags (purple->blue), Invisible Woman, Iron Man 40, Rags (red->green), both Storms, Thor (yellow->green)
and ap stealers: Daredevil, Modern Widow, Original Widow, Psylocke, Yelena
the Hood fits in both categories
and in a pinch any character that can cause a cascade is a decent/good ap generator.