I think this is a good idea, but its very tricky to realize.
Originally I started implementing OH with an Arduino UNO and a TI CC3000.
It took unbelievable long time to implement minimal functionality.
But now that the communication protocols for hybrid objects are clear, it might be worth the effort.
Is it possible to use Web sockets on the ESP8266?
Other then that, I can imagine to implement a http REST fall back channel, which could be used with the ESP8266.
The protocol for the messages are not to complicated and could be handled by the ESP8266 easily.
The remaining trick would probably be a lightweight implementation of what is call the objectEngine. Its a data object that keeps track of data link connections and a process that loops through all resulting changes when ever a new data signals are received.