So far I use a servo with an ESP8266 to control the lightswitch
After running for over half a year now, the voltage regulator got a bit exhausted and I had to add a big capacitor to buffer the current. There was also a bug in the code (string concatenation do not work well for bigger strings in node mcu), which caused it to reboot after some time, but this is also fixed now. Besides that, it is very stable and has low maintenance requirements. Also it is now part of my home automation project https://hackaday.io/project/8791-home-automation
I finally worked again on this project and removed the arduino. The servo is now directly controlled by the ESP8266. The 433MHz Transmitter was also removed, becasue I noticed that I don't use it yet.
To be able to mount circuit on to the servo, I sandwiched all the necessary components between the ESP and a perfboard.
To control the ESP, I used nodemcu and I plan to opensource my code on Github. A link will follow soon.