What a beautiful conclusion.
I also hope that we don't get DBZ power scaling. Personally, I think that future battles will be mostly with WIll himself.
Power corrupts people. That is why dragons in traditional mythology are morally reprehensible wealth hoarders. As extremely powerful beings, they're also incredibly rotten. Now that Will has, in some sense, absorbed the power of a dragon, he'll have to wrestle with that power. Stagnate said as much, but what she said is more or less justification for this whole metaphor.
People seek to control Power, but much more often than not, Power ends up controlling them. Like some sort of demon. The only way to stave off this corruption is a readiness to surrender that Power, and the careful exercise of virtue. Once Power becomes something you cannot relinquish, then it has you - and your virtue will rot rapidly as you do everything can to protect it and expand it.
I'm sure our boy will struggle, but I have faith that he's up to the task.