Our little fairy fail finally became totally ignored. And here's the reason why: you spend 1R and 2 turns to get 1B/1G net worth. Or, maybe, 3B/3G/2R.
Compare it with other common stock+ cards:
Farm. 2 turns, +2 wall, +2 tower, 2B/4G/2R net worth.
Supply units. 1 turn, hand rotation, 3B/3G/2R net worth.
Waterfall. 1 turn, -5 wall, 3B/2G/3R net worth.
White lady. 1 turn, 2B/2G/2R net worth.
Caravan. 1 turn, up to 2B/2G/2R net worth.
Crypt sentry. 1 turn, up to 3B/6G/4R net worth.
Hidden lagoon. 1 turn, up to 4 wall, up to 3B/2G/3R net worth.
Pixie. 1 turn, up to 3B/2G/3R net worth.
Titan's left arm. 1 turn, up to 1B/8G/8R net worth without additional bricks production.
Of course, old Harvest fairy was too strong. Stock gain from Wheat farms was absurdly high, with slight luck you were able to get +12 stock at turn 10 and finish a game with Leviathan, for example. What's the price? You need 3-5 Wheat farms to raise your stock effectively, so you must sacrifice some card slots for it. This price is not too high, I agree.
Wheat farm can be very effective as stock+ mechanism, but only when you manage to collect at least 3 Wheat farms in hand at once. Needless to say, you won't be able to do that (except two cases: a) you're exteremely lucky, b) you use Mask of the phantasm to copy Wheat farm).
I suggest to return to Harvest fairy some of her old power. Change card effect to the following:
"Replace neighbouring cards with Wheat farm".
It would make this card powerful, but also less safe that pre-nerfed version - with that change you can discard something you wanted to play.
What do you think?