I guess I'm the only one that liked the alternate version of the plasma blob? The version in the index was just a featureless orb that was only a few feat above Accelerator's head. It didn't really "look" powerful.
But the version here has it way up in the sky where heavy wind surrounds it along with the clouds being distorted. Sure it isn't as "dynamic" as the orb in the Index version, but it had a much grander feel to it in this episode because the power going into it was expressed better.
At least in this version, there wasn't the excuse that Touma might have been able to dispel it with his hand. This version is way up in the sky. Touma can't ever get up there to touch it with his right hand. I'm guessing Accelerator planned to either have it explode or throw it at Touma. By that point it's already too late to block it. Like the rocks and other debri that Accelerator threw at Touma, the plasma ball (once finished and heading towards Touma) is now already acting on it's own by the natural laws of physics and thus Touma's hand can't block it.
It's only something that violates the natural laws that can get negated by his hand. The Plasma orb as it was forming is still being actively shaped by Accelerator's power and that was the only time Touma could block it.
Though Touma could have gone up and touched Accelerator with his hand. It probably would have suppressed his power during the time he touched him which would destabilize the vectors Accelerator was feeding into the plasma. But the sisters disrupted it instead, so we will never get to find out.
