So is the conclusion actually that the ESP8266 will not respond correctly to a falling edge interrupt or a logic low level interrupt and that therefore it need a low going pulse(high low high) to respond at all ?
Sounds odd.
When the ESP is in Light Sleep mode, yes, the conclusion is that a directional pulse is the only thing it will respond to: either high-to-low-to-high or low-to-high-to-low. The ESP will respond to all those different types of logic changes while it's awake; it's just once it enters sleep mode, it gets very particular about that seeing a directional pulse. If the Espressif documentation wasn't such a mess, that conclusion might have been more clear from the get go.