Filing the I-751 is not optional for your wife, if she plans on keeping her green card. She is expected to be in the United State for biometrics and to attend an interview, if required. You cannot request an interview in your county to remove conditions on her permanent residency. A green card is for permanent residency in the United States, and is not to be used as a tourist visa to come here once in a while. The fact that she has been away the entire time of her conditional residency virtually guarantees that the interview will not be waived. Be prepared to explain why you were away the entire time since she was granted conditional permanent residency. If you do not intend to return, she can file an I-407 to give up her residency and start over once you intent to actually live in the United States. The better plan would have been to not even sponsor her until you were both ready to actually live here.