With only 96KB of data RAM, I don't see how the ESP8266 could be suitable for store-and-forward relaying of aggregated WiFi frames in a moderately busy channel environment where the device isn't guaranteed the immediate opportunity to retransmit what was just received. I don't think RF power would matter, because the computational resources just don't seem sufficient for the mesh to support more than one omnidirectional data stream passing through each node.
Yeah. I believe Espressif may be considering 802.11s mesh support for the newer and better-specced ESP32, but I expect that's probably going to be intended for low-bandwidth applications if it happen.
I am working on a similar project and is interested to know if anyone have had success with hardware addons like external antenna to build a reliable solution?
The chip capabilities are enough to run any low level to moderate load applications like monitoring, actuating and streaming. It is the hardware that I am doubtful about.