If the new 2+ or 2B+ or R2D2 (or whatever it's called) has the USB / PXE that will be a neat bonus.
The ability to boot over the USB bus, using MSD or PxE, is a feature of the SoC. Swap in a '2837 SoC and the capability will be there.
While we're on the subject of overlooked implications... This change will mean that the Pi2Bv1.2 will be able to run a 64-bit OS, should anyone want to do so. Once the CM3 and Pi3A are in the wild, that will be a capability of all Pi lines except the Pi Zero.
I think the willingness to make this change has implications for the future as well. If my contention that the next gen SoC to be used in a Pi will be a 28nm part, it will require less power for the same performance and--therefore--generate less heat. One might expect the possibility of a Pi2Bv1.3 and--potentially--a Pi3Bv1.2, both of which might be "de-rated" versions of a "Pi4B".