bigger, yeah: single sided component placement with bunch of connectors, gpio forrest, LEDs, etc. It's more like a unique SDR development board then a final, compact product now. Look the bright side of this, possibly much less heating issues compared to tiny CHIP (more heat dissipation area)
256 MB RAM can substituted with 512 MB any time during production
Yeah, NAND faster then micro SD card, but who cares? it's not a video processor board so quality SD card should be fine ever. The main reason for microSD is that it is easier for people to flash than FEL process. We had other technical issues which influenced this decision, so not coincidence.
As @Syed said, CHIP is not very easy to come by.