Nah, he was just an arrogant son of a bitch. The reason he never reacted to getting hit hard was because he just couldn't believe that someone could do it in the first place, much less continue to do it. Accelerator probably thought Touma wouldn't be able to keep it up. That arrogance, knowing he's never lost before, led him to believe there was no way he could lose to someone with no power. He is dumb the same way Touma is, where Touma has determination and a need to be the hero, Accelerator just had absolute arrogance.

As for the plasma creation, it's just a natural sense of his abilities, taken up to the maximum. Mikoto does the same thing subconsciously with her Railgun abilities, and the MISAKAs can't because they lost that sensation in the cloning process, and make up for it with the goggles.