?I'm not really all that familiar with how Dormammu is portrayed in the comics, hence why I was asking.
Also, I don't remember any of Touma's forms giving him any significant boost in range. He obviously has the AP to deal with planetary threats, but that doesn't necessarily mean that he can stop some really large creature from swatting away the planet at any given moment, especially if it's intent on avoiding him, and just swatting away the planet from the other side. There really isn't all that much that he can do about it.
But if as you said, Dormammu is normally just human-sized, then there is a debate to be had, for sure.
Dragon King Touma commands the very world itself
Common sense can tell you that's not just referring to the planet