Within the show, her re-souling of Angel could be seen as the beginning. (In fact, it was clearly designed to literally show ‘something new’ coming into her.) From an external view, however, nothing was done with that — except that Willow gradually began attempting magic on her own — and it was never referenced again.

I also saw it less as a need to control everything, than as an increasing pleasure in being able to control things, but I can recognize that’s a matter of personal interpretation.

And, oh yes, I’ve never heard anyone opine that the ‘magic addiction’ theme WASN’T stupid and heavy-handed, there’s just occasional variance in how much it was hated by this or that viewer/fan.