This reminds me of Alpha cards in a bad way - a lot of words for questionable/unreliable benefit. Being a common both the long rules text and unreliability are an issue.

From the perspective of reliability e. g. this might be better if it was an "at the beginning of combat"-trigger that grants +2/+2 or "When this creature attacks, you gain 2 life." depending on the card reveal. But that would make the wording even longer.

Is the top-card-of-the-library thing happening here a larger theme for scouts or just something this card does?

Is the mana value on this relevant, because just going up in cost and have this at

• "Enchanted creature gets +2/+2 and is a Scout in addition to its types.
  Whenever enchanted creature attacks, scry 1 and you gain 2 life."

Is simple and reliable. Even simpler without the scry 1 or without the life gain.

Alternatively you could make player choice matter e. g.:

• "Whenever enchanted creature attacks, you may have it get +2/+2. If you don't scry 2 and gain 2 life."

etc.

The cost of being a one-drop relevant. Checking the top of library feels like a scout thing to me, although I worry about too much of it making for tedious cards when viewing scout as a whole in the set.