Yes, Magneto is a serious powerhouse, we all know that. Has anyone read the Marvel Zombies series? Magneto took them all on in an abandoned city. The man was throwing everybody around. He's his team's biggest threat.
Having said that, I'd still put Thor over him. Mags can't lift that thing due to the magical enchantment, and he can't match him in speed or brute strength. Yes, he has tons of raw energy, but so does Thor. It'd be a good fight, but I'd put Thor over him every day.
Note: If we're using Magneto's electron manipulating power level, then it's only fair we upgrade some Avengers. Odin Force Thor? Classic Dr. Strange?
Magneto's "electron manipulating power level", as you put it, is part of his original powers, as i have already stated. his Original power was the ability to manipulate electro-magnetism.
I see, but could Magneto have the potential to do that?
Magneto definitely has the potential, yes.
Joseph was only different than Magneto because of the 'flaw' in his creation.
it has been stated that all Mutants have a 'built-in' safety measure, that prevents them from overloading their powers, so they don't kill themselves.
Joseph does not have that 'safety measure', thus he was able to reverse Magneto's manipulation of the earths magnetic field, but by doing that he destroyed his own body and became a part of the magnetic field, his mind getting overwhelmed(and presumed destroyed) by the power of the field.