I just want to chime in here with the idea of moving the NOR-flash and PSRAM to the top side to save space for rev 8:
Doing this with a double sided pcb would of course be easier.
Generally populating both sides is more complicated. You need a jig or standoff to hold the pcb when printing solderpaste through the stencil for the second side. And the other issue is that bigger components from the first side could fall off when soldering the second side.
Small components like ceramic caps and resistors will hold on by surface tension of the molten solder. QFN parts with exposed pad often too. But there is a weight/solder area ratio where parts will begin to fall off and have to be glued down with a special glue before. Printing this glue is an extra step. Also it makes rework hard to impossible.