How about replacing +2 cards with +1 card +$1?
That sounds more reasonable, but is probably still too strong.
Comparing your card e.g. to Distant Shore (which also costs $6, but is much harder to access than a full-pile $6 card): Already after two successful plays (rebuilding Estate to Duchy or Duchy to Province), it nets you 4 to 6 VP without penalty, while DS only gives 2+2*1= 4 VP at the cost of two additional junk cards (which de facto reduce DS from a Lab to a cantrip after the first play, and make it even worse afterwards).
Also, a non-digging Rebuild isn't automatically worse than a digging one: Whenever you have an engine that draws your deck or a substantial portion of it, you have a better chance of an Estate/Duchy in your hand than in the rest of your deck. And you'll often have a choice which card to trash, another significant advantage.
I think I would try your card as just a cantrip non-digging Rebuild at $6 (or without any draw at $5). It's certainly more interesting to rebuild from your hand than from digging, as you need other card draw to make it useful.