Maybe my power is not stable (arduino reset not helping me, not needed more as U say *EasyIoT library handles ESP freeze* ), i use 5v charger, then 2 1n4148 diodes in series to get 3.3v, maybe i need add a 470uF capacitor.
Now nodes hangs approx. after 12-48 hours of stable work, then esp blue led stop blinking.
OK, then you can at least spot if its a problem with arduino or with ESP8266. YOu can also try to supply the esp8266 directly, connecting it to your voltage regulator "in parallel" with the arduino - the esp8266 can get quite power-hungry at times.
Edit - and you can add a basic "blink" functionality on LED13 to your arduino, just to see if its still running when your node crashes.
I had similar problem using the dimmer as well. It would connect but not do anything. I found after watch the serial monitor of the arduino, it was getting hung up while pinging. I found if you set your baud rate down to 9600 on all items it works flawlessly. Hope that helps.