His use of fire does seem to have become more controlled, and it's taken pretty casually by the cast. This past season has given me the impression that Spike has been maturing very significantly on the sidelines. We just haven't seen very much of it.
Indeed, while this was definetly his crowning moment of awesome, people tend to forget that an episode before this one Spike also melted wrought iron in 2 seconds with a controlled flame. Little guy's definetly a force to be recokoned with.