I don't feel like I needed more memory or the cpu boost in the pi zero 2. I'd rather they stayed at the old $5 price, decreased power consumption, and added some analog and realtime capabilities. I had thought that was the idea of the RP2440 chip used in the pi pico. It would be great if they added that chip to a pi zero board (maybe in the same SOC as the main processor) so they would have some analog inputs and a somewhat realtime coprocessor.
I've done some fairly fancy Python app development under Linux on a 300mhz embedded ARMv6 board with 64MB of ram, so for lots of things the Pi Zero is already overkill. But an actual OS (i.e. Linux) does make programming a lot easier than an MCU board with an RTOS. So how about a "Pi -1" (minus one) with 1/4 of the resources and power consumption of the Pi 0?