Quote Originally Posted by Buffalobiian
Having that ability would make him immensely, if not overpowered though. Unlike him, Touma doesn't have an off-switch for his arm, and has to think his way through situations to utilise it, or get around its weakness. That's what makes these fights interesting.
Yeah, that must be how it works, for it to work at all (without a plothole). However, I think it reasonable, if things are indeed like that, that Touma should be able to develop his power sufficiently to create an on/off switch, at least to a degree, and also the other way around: to have the ability also elsewhere than just his right hand. It wouldn't make much sense if Touma's power was 100% fixed while others can control theirs as much as they want. That would be nothing but another plothole.