I agree. And considering IMHO the ballistic nylon is one of the best designs I've seen in a smartphone, doing that would be like taking a step back in terms of design. Personally I'd expect BN to hold up better than the wood or leather backs that are offered on the Moto X. I've heard of the wood backs pealing and the leather backs getting scuffs and tears.
BN is made to be tear resistant. It was originally created for flak jackets and is now used for products because of their strength. Will it fray? Maybe. Usually when that happens with nylon I take a lighter and get it close to the fraying material and it will burn itself away. And that's a possible remedy here as well. I've held the MGF Turbo. It has a little more grip overall, but usually the only parts of the phone you grip is the sides. On the BN models, the ring that goes around the sides has a soft touch coating, so I'm not seeing the benefit there.
I definitely wouldn't risk voiding my warranty for it, that's for certain.