The goalpost has shifted from 4 months to 4.5 months

[DPZ2]

I'd happily give them years of radio silence if it meant they'd just axe the current engine, rip out the teetering tower that is the 1.0 code

The 1.0 "code" was abandoned before 2.0 became reality. The underlying game engine, battle mechanics and crafting mechanics were all changed. I am unsure how people still believe that there is any code from the 1.0 version of the game in 2.0 ...

Artwork, some geographical features, and gear design ... those were retained.

The current limitations in code are most likely due to the requirements that the game run on a PS3 at launch.