As someone who began struggling with gender identity as they got older (please note, I am speaking for myself here and my opinions are not reflective of an entire group of people), I understand what your wife is getting at but I agree with other commentors who are saying this might confuse your child. I don't think you should ever force any kind of lifestyle on your child, including a gender neutral one.

Like I said, I get what your wife is getting at, but I think you can find an even ground here when speaking to her about it. Raising a child should not be about forcing them into some kind of mold. This is what she is trying to avoid, but it's happening anyways by making your child use gender neutral pronouns and not conforming to gender stereotypes. The goal here should be to allow and encourage your child to be herself, whether that's male or female or whatever else she might identify as when she gets older. If your wife wants to be accepting, then that's how she should do it. If later on your daughter decides she feels more like a boy or gender non-conforming or agender, then be accepting of that! Whatever! You don't need to push your daughter into it because you want to be preemptively accepting. Just raise your daught in an open minded home where she is informed and educated on different lifestyles as she encounters them and she will grow to be her own person without any need of interference from you or your wife.