Bach's music was not necessarily written for harpsichord, clavichord, or organ specifically. That was why there were arrangements of his music, by himself, for other instruments or groups of them. I can certainly imagine that Bach would love to try his music on piano, even with original, non-arranged version.
For now, I think Goldberg Variation is no way worse on piano than on harpsichord. Try listen more, and you will get the feeling.