for a few fractions of a millimetre here and there, this is pretty much a whole new pcb design. it also meant no magnetically isolated ethernet jacks (the mag in magjack should really be magic instead/), which puts you on a path of doing that isolation your own circuitry, and that… that can put you on the path of feature creep.
yep, feature creep it has, and with that more delay. but for a very good end: that ethernet jack can now do more than ethernet…