Yes, you are right, adds a bunch of passives. Even if we go to a 50:50 voltage divider and can then use one 4x resistor pack for two channels the passives would still take quite a bit of space.
Uh, nasty. I considered the glitch-thing mostly from the ADC perspective, but you are right, the glitches also affect the data lines in an unpredictable way. Open collector busses like I2C are more affected than push-pull. But this adds an issue that is hard to figure out for the end user.
Resistor + Cap will reduce it, but you won’t get rid of it 100%. Opamps are the better solution because they isolate it fully.
A completely different idea for carving out more board space:
Have you considered using a small daughterboard and moving large components onto there? Like NOR flash and PSRAM, because they are large and just have few, shared connections.
The daughterboard could go next to the lcd on the pcb, where the button is. The daughterboard would have castellated edge connectors. It could be manufactured on the same panel as the BP and cut off after reflow. Then the castellated edge connector is hand-soldered onto the bottom side (from Kicad perspective) of the pcb, next to the lcd.
Maybe you’d need a cutout in the daughterboard for the button, so that it can stay at the same height as it is now. Having the button on the daughterboard would be nicer though because then it could be reflow-soldered.
Would something like that fit into the new case?
Would it work if the daugherboard is on a different panel and made with a thinner pcb with like 0.8mm thickness or similar?
How would adding this extra step during manufacturing with like 10 pins hand soldered work out cost-wise?