- ADC (Analog to Digital converter)
- IPv6 (IoT-chip without IPv6, come on..)
- Bluetooth BLE
- Enough RAM to pull of talking many of the protocols you might want to use over the internet.
- etc.. etc..
ESP32 supports this.
I'm making a home weather station with a tipping rain gauge which pulses a switch whenever it tips, and an anemometer that pulses a switch once per revolution.
To make those pulses wake an ESP8266, I'd have to make them reset it. That can work, and many people have done it, but it is annoying. For the anemometer I can switch to just checking the speed when I wake up to check and report temperature. I'd miss short variations in wind speed that way, but that could be acceptable.
For the rain gauge, though, I need to be aware of every pulse. I considered adding a dedicated non-microcrontoller based counter for the rain gauge to accumulate counts between periodic wake-ups of the ESP8266, but that turns out to be more expensive than using a microcontroller. An ATTiny85 could monitor the rain gauge and count the pulses, and could provide in I2C interface to the ESP8266 to make it easy for the ESP8266 to get the results, and would only take one small chip and socket.
That led to me to consider the ATTiny84, which is like an 85 put has several more GPIO pins. Current plan is to use an 84, have it run all the weather sensors and do all the math, and use the ESP8266 just for reporting results. The ATTiny processors can wake from deep sleep on GPIO activity so can deal with the rain gauge and anemometer directly. The ESP8266 can spend its time in deep sleep, only waking up every N minutes to send a report.
You can talk to 1-wire either via I2C (e.g. the DS2482 [1]), or you can easily bit-bang 1-wire via a GPIO or UART [2].
[0] https://www.maximintegrated.com/en/products/digital/one-wire...
[1] https://www.maximintegrated.com/en/products/interface/contro...
[2] https://www.maximintegrated.com/en/app-notes/index.mvp/id/21...
Or do you mean that the ESP8266 has hardware acceleration for IPv4 but not IPv6?