Electrons

When you think about it there's nothing fundamentally wrong with that, since they're both still opposite anyway.

Except that protons aren't fundamental particles (the charge of a proton is made up from the individual charges of its quarks) and there are more particles that you seem to be forgetting. So what you're really asking is for the charges in ALL elementary particles to be redefined: quarks, leptons, bosons etc.

I think you're asking a lot.