To be fair, the explosion would come from a lack of control, not cause of mastering it.
But I see what you mean though. You used that explanation for Broken if I remember correctly so I have an handle on what you mean.
I think the appeal of superhero roleplays comes from the fact people want to experience the thrill of having a power though, so having a solid grip on the power is half the fun. Having to struggle with them is a great starting part, but I see getting old when you have to consciously hold back to document the characters attempt to gain a grip on the power and utilize it properly. Development is fun and all, but it can get redundant when you have to think of ways to show the increasing control. That is my whole perspective on superpowers. Struggle is the starting point for all great characters, but sometimes it is more fun to skip to the end and backtrack later.
With Christian, I see him gaining control rather well because of his more serious nature. He isn't one to fool around so one can imagine he would go out of his way to get some sort of grip on it. Of course, it won't be flawless. I do have plans to show the slip ups in not turning into a cloud of smoke or having an arm or two turn into smokey appendages like a tentacle monster.