I suggest for playability add a cantrip, like Niveous Wisps or Pressure Point?

Eh; sometimes the simplest iteration of a card is good enough. It's not going to be a contender for worlds best card; but it's perfectly useful in limited.

If I were to add anything to it; I'd be tempted to try and make it able to act fast enough to stop abilities. But that aint common no mo, bro.

Would "Tap target permanent" be terribly out of line?

V: There's no way this is useful in limited. For your restricted set of 4-8 noncreature spells, even Pressure Point and Niveous Wisps got cut moderately often. Spending a whole card to neutralise one creature for one turn? Ugh.

JMG: I fear that's not white. I don't really know why... white can tap creatures, and also artifacts (Auriok Transfixer). I guess it's against the possibility of tapping lands, which is blue or (bizarrely) black, although colourless can also do it (Rishadan Port, Icy Manipulator). It'd probably be fine as a minor bleed if there was a good reason. But there doesn't seem to be much reason to make this white Enervate, rather than white Pressure Point or blue Enervate.

I was thinking more 'Reverse Burst of Energy', but I agree that basing color identity on any 20th century card is a fallible argument.

It needs something else, considering it's significantly strictly worse than Dispatch. Even if it was a cantrip, I still probably wouldn't run it in Limited.

That seems like a mistake to me. One cost cantrips in limited are pretty good, even if they have no effect. Since limited decks rarely curve out, it would kind of be like drafting a card that let you play with a 39 card deck.

That said, I could easily see myself not drafting that card because there are better picks in the pack. But if I did happen to draft one, I'd probably play it in all but the most bomb-heavy decks.

Well, I never claimed to be good at Magic. I guess your statement (wouldn't draft, not wouldn't play) is more accurate.