Off course the ultimate is being able to debug on the arduino itself. However there will always be limitations (like no debug support) which make the simulator second best. However there are currently no good (affordable?) simulators.
So yes I have been porting (This is the official term) Arduino code to the PC, like you have. This purely for debugging purposes and only for "not really arduino oriented code". The biggest pain I have is the arduino and AVR defined variables.
Do not include Arduin.h and you get problems with PROGMEM and many others. Do include Arduino.h and you have problems with stuff you don't need.
Conclusion: I am interested in a Arduino.h ported to PC world.
Best regards
Janje